Fruit Trees Can be a Nightmare for Tri-Cities Gardeners

Fruit Trees Can be a Nightmare for Tri-Cities Gardeners

Marianne C. Ophardt
Washington State University Cooperative Extension
Area Extension Agent  

It=s a nice dream.... being able to grow fruit right in your own backyard.  However, this dream often turns into a nightmare for many home gardeners who are not aware of how much work it can take to grow acceptable quality worm-free fruit.  It requires regular sprays of insecticides to keep apple and cherry fruit free of worms.  Even if you tire of spraying and are willing to sacrifice your fruit to the Aworms@, residents of Benton and Franklin counties are required by law to control the wormy pests on apples, crab apple, hawthorn, and cherries.   The obstacles to growing backyard fruit trees often leads to many questions from would-be backyard orchardists when they discover that their dreams aren=t easily realized.  Here are some of their frequently asked questions... and answers.

Why do Benton and Franklin counties require me to spray my apple and cherry trees?  Backyard fruit trees, where codling moth and cherry fruit fly are not controlled, serve as a source of infestation for commercial orchards.  Infestations of codling moth and cherry fruit fly in nearby backyard trees mean a grower will have to use more insecticides or additional pest management strategies to control these pests in his orchard.  This leads to increased costs and an increase in the amount of pesticides used.  The infestation may also lead to infested fruit within his crop, which could mean the grower will get less money for his crop or it may even mean he can=t sell it at all.  Because commercial tree fruit production is a significant part of our local agricultural economy, it=s important to keep backyard fruit trees from becoming a liability to commercial growers.

How difficult is it to control these pests? Both codling moth and cherry fruit fly require regular sprays, generally every 7 to 10 days, during the growing season to keep the fruit Aworm free@.

Spraying trees is time consuming ... you have to mix the sprays, apply them, and clean up afterwards including laundering your clothing.  You also need the right equipment for spraying.  If the trees are large, you=ll need more than a hose-end or garden sprayer to reach the tops of large fruit trees.  It=s unsafe to spray fruit trees using a ladder.  You also should wear protective goggles, long sleeves, long trousers, a hat, and shoes when applying pesticides to your trees. These items must be laundered separately from other laundry right after spraying.

The weather can definitely make it difficult to apply the regular sprays needed to keep pests in check.  You should not spray when the temperature is expected to go below 40 degrees when applying dormant oils and you should not spray when the daytime temperature is above 85 degrees when applying sulfur or petroleum-based sprays. Wind can lead to the spray drifting off target, so you should never spray when there=s any noticeable wind.

If I apply a dormant spray, won=t that take care of the wormy pests?  No.  The dormant fruit tree sprays that are applied in the late winter just as buds start to swell are aimed at controlling diseases, not insects.  Dormant oils which should be applied just before the buds open in the spring, only help control certain insects that overwinter on the bark of the tree, such as aphids, scale, and mites.  The dormant oils have no affect on codling moth or cherry fruit flies.

I don=t like using so much pesticide.  Is there any organic way to control these pests?  Some organic sprays are available for codling moth and cherry fruit fly control, but most don=t provide adequate control to keep the home orchard worm-free and most would also require more frequent application.  Codling moth can be controlled without sprays, if you are willing to thin and bag all the apples on a tree using special paper bags. 

I=ve heard about the use of pheromones (insect hormones ) to control codling moth in apple orchards.  Wouldn’t that also work for a backyard orchardist like me?  The lures impregnated with insect sex pheromones are useful tools in codling moth management in large orchards.  The lures are placed around the perimeter of an orchard to confuse male moths looking for a mate.  Unfortunately, the lures have proven ineffective when dealing with small orchards or backyard fruit trees because mated females can come from nearby sources to lay fertile eggs on the apples.  Infested trees close to large apple orchards using lures for codling moth management increase the amount of spraying needed to keep the codling moth out of those orchards.

What about the insect traps advertised in garden catalogs?  Won=t they work in controlling the adult codling moth and cherry fruit flies?  The catalogs may be misleading you.  Codling moth traps are good tools to use to monitor the presence of these pests, but are not effective in eliminating damage because they attract only the male moths looking for a mate.  Again, fertile females can come in from nearby sources to lay eggs.. The yellow color and an ammonium carbonate bate on cherry fruit fly traps are what attract both male and female adult flies.  However, the traps are not considered adequate for good cherry fruit fly control.

Is diazinon still available to home gardeners to use on apples and cherries?  What pesticide can I use to control codling moth and cherry fruit fly?  There is still a number of home garden diazinon products commercially available that can be used on backyard cherry trees but only a few products are labeled for use on apples.  However, these products may not be readily available at your local garden store.   If you find a home garden product containing diazinon, be sure the label says it can be used on the type of fruit tree you have.  It is illegal to use the product on cherries or apples if they aren't listed on the label.

You may want to look for a home garden insecticide product containing a combination of malathion and methoxychlor for use on apples.  There are quite a few of these labeled as Afruit tree spray@ or Ahome orchard spray@ and most also contain a fungicide, captan, for disease control. 

Why shouldn’t I grow hawthorns and crab apple?  Their fruit also becomes infested with codling moth and can pose the same threat as infested apple trees do to commercial orchardists.  If you have a hawthorn or crab apple in your yard and it=s infested with codling moth, you must spray it regularly.  

How about ornamental flowering cherries?  Are they a problem for commercial growers?  Your ornamental Japanese flowering cherries don=t produce fruit and shouldn’t pose a threat to commercial cherry growers.  However, sometimes the rootstock from below the graft of a flowering cherry starts to grow.  It will usually be a cherry that produces fruit.  These shoots from the understock should be removed when they appear.  If the understock is the only part of the tree that=s still alive, then the entire tree should be replaced. 

Since apples and pears require so much spraying to keep them worm free, are there any other types of fruit trees I can grow without a lot of spraying?   There are no common wormy pests of apricots, peaches, nectarines, and plums that require regular spraying of the trees.  Your best bet is to grow plums, they don't require regular spraying and have a more reliable crop than peaches or apricots.

The Horsechestnut or Buckeye

The Horsechestnut or Buckeye
Marianne C. Ophardt
Washington State University Extension
Area Horticulture Specialist
The common horsechestnut (Aesculus hippocastanum)is a big tree at maturity reaching 75 to 100 feet in height with a spread of 40 to 70 feet. You can see one of these big guys at the Benton County Courthouse in Prosser.  As you will note, this tree is best suited to parks, arboretums, and building with large expanses of lawn area.  It really isn’t one that most people should plant in their yards.
The nuts are produced in spiny capsules which are a nuisance with the large numbers produced by a mature tree. The nuts, with and without the spiny capsules around the outside, are popular ammunition for children.  While you can’t eat these nuts, they are fun to collect.  You can even start you own horsechestnut tree quite easily.  Just take some moist potting soil and place in a plastic container with a cover.  Bury several nuts in the potting soil.  Close the container and put it in the vegetable bin of your refrigerator for three months or more.  Late next winter or early in the spring take them out and plant them outside where the soil will be kept moist.  Treated this way, the nuts will germinate and grow.  If you give this a try, only use fresh nuts and “plant” them in your refrigerator soon after harvest.  If the nuts dry out, you’re out of luck.  This is an activity kids will love to help you with.  Just make sure you have room to grow this big tree.
Here’s a special note about chestnut “nuts.” Native Americans did use horsechestnuts as a food source, but only after they leached out their poisonous compounds in boiling water.  However, horsechestnuts should definitely be considered poisonous.   
The edible chestnut looks quite different from the inedible horsechestnut.  The edible chestnut has a dense, dangerously spiny capsule and the horsechestnut has a capsule with shorter, less dense spines.  The edible chestnut is somewhat rounded with a slightly pointed end.  The horsechestnut is smooth with no point and sometimes flattened a bit on one side.  Looking at the tree’s leaves also helps.  Horsechestnut leaves are compound and consist of five or more “fingers” or leaflets. Edible chestnut leaves are single, entire leaves.

Sycamore Problems

Sycamore Problems

Marianne C. Ophardt
Washington State University Cooperative Extension
Area Extension Agent

Lace Bugs

Just this past week, several people have brought me samples of ailing sycamore trees.  On each of these samples there were two problems worth mentioning.  One problem was an insect, the sycamore lacebug.  It’s a tiny bug with lace-like wings.  It sucks sap from leaves creating a speckled appearance. The lace bugs can be found on the undersides of leaves along with small black specks of their excrement.   When feeding is severe, the leaves take on a brownish or dry look. 

The lace bug has not become a serious annual problem on sycamores, but it does show up from time to time.  The amount damage it causes is typically insignificant and tends to only become extensive in late summer or early fall.  With damage occurring so late in the season, control is not needed.

Herbicide Injury

The other problem evident on these samples was more noteworthy.  The leaves were somewhat malformed and cupped downward with an excess of the leaves’ natural hairy fuzz.  This is a sure sign of herbicide injury.  It was very likely caused by applications of “weed and feed” products to the lawn.  Dicamba or 2,4D, commonly found in “weed & feed” products, were probably the herbicides at fault.  Sycamores are particularly sensitive to damage from these two herbicides.

The downward cupping of the leaves is not critical. After all, the tree will soon be losing these leaves in preparation for winter.  The real damage from these lawn herbicides happens to the trunk of the tree.  Both herbicides can lead to damage of bark tissues and the emergence of bark eruptions on the main trunk, usually more extensively on the lower portions of the trunk.  The bark loses its beautiful mosaic pattern and smooth appearance.  It becomes rough and fissured.  Immediately beneath the eruptions, the bark tissue is pink and spongy.  Beneath the eruptions, the inner wood becomes dark brown.  This damage may later attract a borer, the American plum borer, which then causes even greater damage to the bark and trunk tissues.

Dicamba and 2,4 D can cause damage to sycamores even when applied at the correct rate, but greater damage occurs if they’re over-applied.  Over-application often occurs when home gardeners don’t calibrate their drop-spreader or sprayer before applying a “weed and feed”.  As a rule, 2,4 D and dicamba should not be applied in a general application to the lawn over the root zone of sycamores.  Spot treating weeds is safer for the sycamores and more economical.

Leaf Scorch

Yet another problem being noted by some sycamore owners is leaf scorch.  This shows up as bright yellow to brown leaves scattered throughout the crown and accompanied by substantial leaf loss.  The leaves most severely affected are the oldest... especially the inside leaves.  The most likely cause of this problem is heat and drought.  It’s been a hot summer.  Sycamores are big trees and if they don’t get enough water they let you know.  Lack of deep watering, girdling roots, and compacted soils can all be factors in a sycamore becoming drought stressed.

Trees to Consider

Trees to Consider

Marianne C. Ophardt
Washington State University Extension
Area Horticulture Specialist

Smaller SpecimenTrees for the Home Landscape

AMUR MAPLE (Acer ginnala) 15-25'. A multi-stemmed tree. Excellent as a specimen tree with striking red fall color and clusters of small fragrant, yellow flowers in early spring. Winged fruits add interest. Tolerates wide range of soil conditions and heavy pruning.

HEDGE MAPLE (Acer campestre) 25-35'. A nice maple for use in the home lawn. Withstands severe pruning. Tolerant of alkaline soils. The very dense crown will need thinning to permit grass to grow below.

TATARIAN MAPLE (Acer tataricum) 15-20'. A small tree for planters or street locations. Tolerant of adverse conditions. Red to red brown fall color.

EUROPEAN HORNBEAM (Carpinus betulus) 40-50'. Durable small to medium tree. Also available in smaller columnar form.

RED BUD (Cercis canadensis) 20-30'. Heart shaped leaves, early purplish-pink flowers. Tolerant of alkaline soils.

PAGODA DOGWOOD (Cornus alternafolia) 25'. White flowers in May-June. Horizontal branching habit. Very hardy. Not very available.

FLOWERING DOGWOOD (Cornus florida) 20-40'. A favorite of many people but it is difficult to establish here. It needs pampering with protection, careful watering, acidifying fertilizers, and an organic mulch. It does better in partial shade!

KOUSA DOGWOOD (Cornus kousa) 20'. Early summer flowers and bright red fruit make this shrub-like tree an interesting specimen. Fruit can be a litter problem if near walks, patios or driveways. Rich red fall color!

CORNELIAN DOGWOOD CHERRY (Cornus mas) 20-25'. Small shrubby tree. Very early yellow flowers.

GOLDENRAIN TREE (Koelreutaria paniculata) 30-40'. Attractive yellow flowers, excellent as a small lawn tree, tolerates our climate and soil conditions well.

SAUCER MAGNOLIA (Magnolia soulangiana) 20-30'. Beautiful spring flowers. Prefers acid soils.

STAR MAGNOLIA (Magnolia stellata) 15-20'. Shrub-like tree with beautiful fragrant flowers. Prefers acid soils.

FLOWERING PLUM, CHERRIES, ETC. (Prunus sp.) Many different forms of different sizes, shapes, fruiting and flowering characteristics. Many are worthwhile. Consult: Manual of Woody Landscape Plants by Michael Dirr, Sunset Western Garden Book, and The World of Trees from Ortho.

CALLERY PEAR CULTIVARS (Pryus calleryana) Variable size, according to cultivar. Good flowering and fall color.

JAPANESE PAGODA TREE (Sophora japonica) 50-75'. Lovely flowers, difficult to establish, good tree for city lots.

JAPANESE STEWARDIA (Stewardia pseudocamellia) to 30'. White camellia-like flowers in June, rich red-maroon fall color, unusually mottled bark.

Large Shade Trees for the Home Landscape

RED HORSECHESTNUT (Aesculus x carnea) 30-40'. This tree is not for small yards. Its true beauty is its dark green foliage and deep red flowers. Very showy when in bloom.

RED MAPLE (Acer rubra) 50-70'. Rounded tree with good red fall color. Good for poorly drained sites.

SUGAR MAPLE (Acer saccharum) 60-120'. This is an excellent shade tree but it needs plenty of room. Orange to yellow fall color. Has some disease problems.

RIVER BIRCH (Betula nigra) 40-70'. This birch does best in moist soils and prefers an acid soil, but can be grown here if acidifying fertilizer is used. One of the most trouble-free birches and is resistant to bronze birch borer. It has an apricot colored peeling bark that is an attractive feature. ‘Heritage’ is a considered a superior selection that has good vigor and grows relatively fast.

WHITESPIRE WHITE BIRCH (Betula platyphylla japonica 'Whitespire Senior'). The only white barked birch which is bronze birch borer resistant. You must have 'Whitespire Senior' for resistance to borer.

GREEN ASH (Fraxinus pennysylvanica) 50-60'. A popular shade tree with two bad points. It has a big problem with aphids and other insects and the seeds and seedling create a nuisance. Look for 'Marshall's Seedless' cultivar for a seedless vigorous tree. Ash borers are beginning to devastate this tree and you may want to reconsider planting it.

THORNLESS COMMON HONEYLOCUST (Gleditsia triacanthos var. inermis) 30-70'. A "perfect" tree for filtered shade. A relatively new insect problem (honey locust pod gall midge) had made the tree less than "perfect." Avoid the 'Sunburst' cultivar because of this insect pest.

KENTUCKY COFFEE TREE (Gymnocladus dioicus) 60-75'. This large tree is adaptable to our harsh growing conditions. Its bark has an interesting pattern. One problem with this tough tree is the litter it creates with its seed pods and leaves. Use only in large areas.

AMERICAN SWEETGUM (Liquidambar styracifula) 60-75'. Needs room to develop roots but it is a nice tree with excellent fall color and corky bark. Prefers an acid soil and should be fertilized with an acidifying fertilizer. Few insect problems in our area. 'Moraini' is an excellent cultivar with a faster rate of growth.

AMERICAN HOP HORN BEAM (Ostrya virginiana) 25-40'. A nice, medium sized tree with many horizontal and drooping branches. Tolerates partial shade. Slow to establish.

PERSIAN PERROTIA (Parrotia persica) 20-40'. Here’s a tree with few pest problems and it has very nice shiny leaves and exfoliating bark. It’s yellow-orange-scarlet fall color is unsurpassed by any other tree. This is the perfect landscape tree. If you can find it, plant it.

LONDON PLANE TREE (Plantanus x acerifolia) 70-100'. Warning: this is a sycamore and it's a BIG tree! Select only anthracnose and powdery mildew resistant cultivars. One cultivar, `Yarwood’ is very resistant to powdery mildew and fairly resistant to anthracnose. ‘Bloodgood’ is very resistant to anthracanose. `Liberty’ and `Columbia’ are two other cultivars that have been touted as being anthracnose resistant, but they’re apparently only resistant to eastern strains of the disease and not western strains of the disease.

RED OAK (Quercus rubra) 60-75'. An oak with relatively fast growth. Red fall color. Relatively few insect and disease problems. Interesting furrowed bark. This tree needs room, give it plenty of space to grow into.

ENGLISH OAK (Quercus robur) 40-60'. Tolerant to eastern Washington conditions. Also a narrow columnar form is available.

LITTLELEAF LINDEN (Tilia cordata) 60-70'. An excellent shade tree. Aphids may be a problem. Can be pruned into a hedge form.

SILVER LINDEN (Tilia tomentosa) 50-70'. A very nice shade tree with attractive foliage. Top of leaves are green, bottom sides are silver. Fragrant flowers in July. Tolerates heat and drought fairly well. Nice smooth gray bark. Aphids may be a problem.

CHINESE ELM (Ulmus parvifolia) to 50'. Small to medium sized tree. Relatively problem free. Interesting mottled bark. Quite drought and alkaline soil tolerant. Not to be confused with the Siberian Elm (Ulmus pumila).

JAPANESE ZELKOVA (Zelkova serrata) 50-80'. A handsome tree with an interesting growth habit. Somewhat difficult to establish. Look for the cultivars 'Village Green' and 'Halka'.

Windbreak Trees

Windbreak Trees

Marianne C. Ophardt
Washington State University Extension
Area Horticulture Specialist

It's been said that the Tri-Cities is a windy area. You betcha! You’ll get no argument from most area residents.  Wind erodes our soil and leads to nasty dust storms. Winter winds can increase a home's heating costs by 10 to 40 per cent.  Wind can also be just plain annoying.  You can't stop the wind, but you certainly can slow it down with strategically placed trees and shrubs ... windbreaks.

"A windbreak is a planting usually of both trees and shrubs that is designed and established to reduce the undesirable effects of strong winds," says Don Hanley, WSU Extension Forester.  Early settlers in the treeless areas of Washington and the rest of the Northwest needed trees to provide much needed shade and protection from the wind. Farmers planted fast-growing species of trees in a simple one to six row design. Single species of trees, such as eastern cottonwood, black locust, and Lombardy poplar, were planted fairly close together.  Not all these windbreaks were successful ... improper placement or poor selection of the tree species meant a failure to obtain the goal of diminishing the wind.

Things haven't changed much since the days of those early pioneers.  Farmers and homeowners are still planting windbreaks and still having limited success.  The main reason for the failure of windbreak plantings is that many are not given adequate care to get them off to a good start.  Plantings often succumb to a lack of water, competition from weeds, damage by livestock, mechanical injury from mowers and other equipment, and careless use of weed control chemicals. Windbreak plantings are just like any other landscape planting, the trees need care and attention to be able to live and grow.

While the pioneers had to guess what trees to use and where to plant them, scientific research has revealed the proper design, location, and types of trees that will provide the most effective windbreaks.

Planning

These are the things you should consider when planning your windbreak:

• The location that the windbreak will be most effective.
• Do you have enough space for a windbreak?  How many rows will you plant?  The most effective windbreak has five rows of deciduous and evergreen trees and shrubs.
• What species are best adapted to the area and your situation?
• Is there irrigation available to provide them with the needed water for establishing and maintaining them?
• Will the trees create a problem when they reach their mature size?

Placement

Our local prevailing winds tend to come from the west, but this may vary slightly depending on your situation and topography. A windbreak should be located so that it’s at a right angle to the prevailing winds, or as nearly as possible to a right angle. The closer it is to the right angle, the more effective it will be.

To be effective, the windbreak should be no more than 100 feet from the house.  At this distance, trees 35 or more feet tall break and lift the wind currents over the top of the home,  You can place the windbreak closer but make sure the trees don’t shade the house. 

The windbreak should also extend fifty feet beyond the length of the house and the area you want protected.  If you must have gaps in your windbreak rows to accommodate irrigation ditches, paths, driveways, etc., try to make the crossings at oblique angles so you don’t create your own sort of “wind tunnel.” 

Number of Rows

Many people usually plant only one-row windbreaks. However, the more rows you plant, the more effective the windbreak.  If there is not enough room available for a full five rows, consider four or less rows. Be sure not to crowd the rows though.  Crowding slows growth and weakens the plants. Lower limbs of crowded trees tend to die out due to heavy shade.  Trees should be staggered between rows.

If there is only room for four rows, the best protection is achieved with a row of dense shrubs, a row of medium evergreens, a row of tall evergreens, and a row of medium evergreens.  With three rows you’ll get the maximum protection with single rows of a dense shrub, a tall evergreen, and a medium evergreen.  With two rows, you’ll want to use a medium evergreen and a tall evergreen. If you only have room for one row ... use a tall evergreen, such as arborvitae.

Spacing

The spacing between rows should be sixteen feet.  The spacing between plants in the rows should be:

Tree/Shrub Type

Multiple-row Windbreaks

Single-row Windbreaks

Dense Shrubs

3

2

Medium Deciduous Trees

9

6

Tall Deciduous Trees

12

8

Medium Evergreen Trees

9

6

Tall Evergreen Trees

12

8

These spacings give the trees and shrubs room to develop full dense crowns before they start growing together.

Another option for design is a twin-row, high density windbreak which can be used when space between the home and planting is limited.  With this high density design, the two rows of trees are planted six feet apart and the trees are planted five to eight feet apart within the rows.  The same species may be used in the twin row.  Additional twin-rows can be placed 25 to 50 feet away, allowing for the planting of gardens between two twin rows.  The distance of 100 feet between the house and the windbreak can be reduced. The spacing of the trees facilitates watering by drip irrigation. 

Planting

No windbreak will succeed if the plants aren’t planted right.  As with any landscape planting, you should prepare the soil first.  You may find it easiest to till the soil along the row.  Till the soil to a depth of 18 inches, or more if possible.  Then dig a trench deep enough to accommodate the roots of the trees. The top of the root ball should be at soil level or just a little above to allow for the soil settling.

Place the trees in the center of the trench or hole so that all the tree roots are in a downward position. Hold the tree while filling the soil back in around the roots.  This is probably easiest when done by a team of two people or more.  Gently firm the soil around the roots and then water the trees in with a thorough application of water.

Apply a slow release fertilizer at the rate recommended on the label. Don't over-fertilize because the fertilizer salts can damage the young roots of the plants. 

You can encourage growth of the trees and shrubs by topdressing with an application of fertilizer each spring just as new growth starts to unfold. Look for an acidifying fertilizer to help lower the pH or alkalinity of the soil. This is most important with evergreens because they generally prefer slightly acid soils.  Many local soils are quite alkaline, unless they have been under irrigation for years.

 Weeds and grass growing around the trees can impede growth by robbing them of needed nutrients and moisture.  A three to four inch thick layer of wood chip or bark mulch will be beneficial in keeping down weed growth and maintaining soil moisture.  Mulch the entire root zone if possible, but keep the mulch several inches away from the tree trunk.

The most successful windbreaks are those with live and growing trees.  Provide the needed water and care to help the trees establish and thrive.  Be sure to provide protection from animal and equipment damage. 

Time To Grow

If planned and planted properly, it will only take about three to four years before you start noticing the protection that your windbreak is providing.  Within seven years the windbreak should be providing effective protection to you and your home.

For more detailed information contact your local WSU Cooperative Extension office for the bulletin "Trees Against the Wind."

What Types of Plants Do Best In Windbreaks

Early pioneers planted a variety of fast-growing, soft-wooded, short-live tree species, such as Lombardy poplar, willow and cottonwood, for their windbreaks. Many of these fast-growing trees are still recommended and used for modern farm windbreak use.  However, homeowners should be aware that most of these are very invasive and have extensive root systems that can be a problem with septic systems, driveways, swimming pools and elsewhere.  These species also tend to be short-lived, such as with poplars which start to decline after about fifteen years.  The only advantages to using them are that they are inexpensive and they grow quickly. There are better plants that will provide more effective, long-term windbreaks.  Here are some:

Deciduous Shrubs

Mature Height (feet)

Crown Height (feet)

Common lilac

10

10

Tartarian honeysuckle

8

7

Common privet

10

8

Nanking cherry

6

4

Tall Evergreen Trees

12

8

Evergreen Shrubs

Mature Height (feet)

Crown Height (feet)

Mugho pine

8

8

Deciduous Trees

Mature Height (feet)

Crown Height (feet)

Fastigiate European hornbeam

35-40

20-30

Fastigiate English Oak

50-60

15-20

Littleleaf Linden

60-80

35-55

Hedge maple

25-35

25-35

Evergreen Trees

Mature Height (feet)

Crown Height (feet)

Arborvitae(Northern White Cedar)

35

20

Scotch pine

40

20

Austrian pine

40

30

Blue spruce

40

25

White fir

30-50

15-30

Nordman fir

40-60

Douglas fir

60

25

Rocky mountain juniper

20

15

Eastern juniper

25

15

Franklinia and Chitalpa Trees

Franklinia and Chitalpa Trees

Marianne C. Ophardt
Washington State University Extension
Area Horticulture Specialist

You’ve probably never heard of the Franklinia tree or the chitalpa tree.  They’re both uncommon trees that you’re not likely to find growing in this region. However, I think it would be interesting to try them and see how they well they would grow here. Don’t run to your local nursery and ask for these trees.  They’re not readily available and will probably only be something you can find in a specialty nursery catalog.

Let’s talk about the Franklinia tree.  It has a fascinating history.  It was first discovered in 1765 in Georgia by John Bartram of Philadelphia.  While Bartram’s occupation was that of gentleman farmer, he also studied philosophy, religion, medicine, and science.  It was his interest in plants and botany that gained him a place in history.  He made many botanical expeditions throughout the “New World” and earned himself the title of King’s Royal Botanist for North America from King George III of England.  

It was on one of his expeditions to Florida that John and his son William came across a beautiful blooming tree or shrub along Alatamaha River in Georgia.  Because they were anxious to reach their destination, they didn’t stop to collect samples. Ten years later William headed back to Georgia in hopes of finding and collecting specimens of this special plant.  He found the plant, retrieved specimens, and took them home to propagate them. William named the plant, Franklinia alatamaha, after his father's good friend Ben Franklin.

What makes the story interesting and the plant so rare, is that when a visit was made to the same location in 1803 the plant had disappeared.  No other native stands of this particular plant were ever found again.  It’s believed that all the specimens of the Franklinia tree in the United States and around the world come from those collected and propagated by William Bartram.

Apparently the Bartrams saved the Franklinia tree from virtual extinction.  This makes the tree very fascinating, but it’s the tree’s characteristics that make it truly special.  It’s a cousin to the camelia.   Large white flowers emerge from marble-size buds in late summer and continue coming along well into fall.  The flowers are three inches in diameter with an orange center and a delicate fragrance.  These remarkable flowers are sometimes still present when the tree starts to turn orange to red in the fall.

The Franklinia tree is a small deciduous tree or large shrub with an upright spreading form and an open base.  It usually only grows to about twelve feet in height, but there have been reports of taller trees. The tree is slow growing and difficult to transplant.  It requires a moist, acid, well-drained soil that high in organic matter.  While the Franklinia tree is winter hardy for our area (USDA Zone 5), it may not do well here because of our intense summer sun.  If tried in our region, it should be planted where it will be shaded from the sun during the heat of the day.  It would also be best to prepare a landscape bed for this special tree by adding compost or peat moss to the soil, along with mulching the tree with bark or compost and keeping the soil evenly moist. 

If you know of one growing in this region, let me know.  Last year to commemorate the 300th anniversary of John Bartram's birth, Martha Leigh Wolf of the historic Bartram's Garden in Philadelphia started a census of Franklinia owners wanted to “find out how far north and west the fabled plants grew, under what conditions they thrived, how long they could live, and how big they could get.”  They surveyed members of the American Association of Botanical Gardens & Arboreta and the Garden Writers Association of America. What they thought would be simple survey turned out to be much bigger with replies far beyond their expectations.  The little survey evoked hundreds of responses from all over the United States and as far away as New Zealand and Germany.  One gentleman even sent a picture of a Franklinia that he had taken in Korea in 1950.  Apparently, the Franklinia tree is beloved by its owners who know they are growing a very special and rare tree.

The chitalpa ( x Chitalpa tashkentensis) doesn’t have a similar rich history, but it is an interesting tree.  It’s not a native tree but a hybrid created in Uzbekistan by Nikolai Rusanov in 1964. It’s what is called a bi-generic cross... a cross between two genera of plants, the desert willow (Chilopsis linearis) and catalpa (Catalpa bignoides).   The chitalpa was first introduced into the United States by Robert Heff of the New York Botanic Gardens in 1977. 

The chitalpa is a fast growing deciduous tree or shrub with spreading‑arching limbs that form a dense broad-oval crown. The mature size is believed to be around 20 to 25 feet tall, but it hasn’t been around long enough to know for sure. This vigorous tree is drought resistant and able to withstand strong winds without breakage. 

The chitalpa’s parents are “messy” trees because of the litter they create with dropped flowers and many long seed pods.  However, the chitalpa is much better behaved. That’s because it’s sterile... not producing seed pods.  The sterile flowers also dry on the tree rather than dropping to the ground right after bloom. 

Perhaps the main drawback to growing the chitalpa in this region is that it may not be totally winter hardy.  It has withstood temperatures as low as nine degrees Fahrenheit, but it’s likely to die back to the ground after severely cold winters in our region. Its other characteristics that may be troublesome are is its tendency to sucker near the base and its susceptibility to mildew in cool weather. 

One of the best things about the chitalpa is its flowers.  The cultivar 'Pink Dawn’ produces numerous clusters of showy pale pink flowers in the summer.  Each cluster contains 15 to 40 one-inch long flowers with ruffled petals and lavender throats. The leaves are narrow and glossy.  Another cultivar ‘White Cloud’ is a bit less showy with white flowers.

It’s not easy to find sources of these two trees.  You can get both ‘Pink Dawn’ chitalpa from Forest Farm in Williams, Oregon at (541) 846-7269.

Ginkgo Trees — A Link to the Past and Good Trees for the Present

Ginkgo Trees — A Link to the Past and Good Trees for the Present

Marianne C. Ophardt
Washington State University Extension
Area Horticulture Specialist

There’s a lovely row of old ginkgo trees in the parking lot at the WSU Research and Extension Center in Prosser,WA.  They were planted there many years ago and have grown into very nice specimens.   However, it wasn’t long ago that some employees wanted to have the trees cut down.  The problem was that several of these ginkgo trees have turned out to be female fruit producing trees.  The awful smell of the over-ripe fruit is what caused some to want the trees’ removed.  This is truly a nose-pinching smell akin to dog manure or worse. Pee-yuu! 

Although the smelly fruit do present a distinctly unpleasant problem, those at the center who wanted to keep these old ginkgo trees prevailed... and the trees have remained unscathed.  I’m glad.  Ginkgos are a living link to the prehistoric past... having originated over two hundred million years ago.  Once common in North America and Europe, the ginkgos were wiped out during the ice age and disappeared from North America seven million years ago and from Europe three million years ago.  Ginkgos were thought to be extinct until 1691 when a German physician and botanist, Engelbert Kaempfer, found ginkgos growing in Japan.

Kaempfer may have found the “lost” tree, but it was Buddhist monks who most likely saved this living fossil from extinction.  From about 1100 AD, Buddhist monks in the mountains of south-east China cultivated ginkgo trees in the courtyards of their monasteries.  The ginkgo trees were valued for their medicinal uses, edible seeds, and perhaps their beauty.  In about 800 AD, the monks brought the ginkgo with them to Japan where many years later Kaempfer found it.

Kaempfer was in Japan for two years (1690-1692) on a mission for the East‑India Company. When he wrote about his discovery in 1712 he called ginkgo trees "Amoenitatum exoticarum". At some point he brought ginkgo seeds to Holland.  It’s believed that one of the first ginkgos to be “replanted” in Europe was at the Botanical Garden in Utrecht ... where it’s still growing today.  In 1754, a ginkgo was planted at Gordon, the English botanical school, and in1762 at Kew Botanical Gardens.

From England, Holland, and Japan the ginkgo was gradually reintroduced to Europe and North America.  In 1784 a ginkgo was planted in William Hamilton’s garden in Philadelphia.  It then took about a hundred years for the ginkgo to become a popular street tree in east coast cities.  It was made more popular when famous architect Frank Lloyd Wright picked it as his favorite tree.  It’s now found in landscapes and cities across our country.

Not only is the tree’s “lost and found” history quite interesting, it’s an extraordinary tree in other ways too.  Botanists relish the ginkgo.  What particularly excites botanists is that the ginkgo has sperm that have flagellae, making them mobile.  Among living seed plants the trait of flagellate sperm is only shared with cycads.  These swimming sperm are found inside the ginkgo pollen grains. 

Ginkgo trees are dioecious with separate male and female trees.  The pollen is moved from male to female trees by the wind.  The female tree is pollinated in the spring when a pollen grain lands on one of its ovules.  However, actual fertilization of the ovule by the sperm doesn’t happen until the fruit matures, drops from the tree, and the stinky, fleshy seed coat rots away. 

Ginkgo bilobas are the only living members of the Ginkgo family which once consisted of at least 18 members.  All these other family members were lost millions of years ago. Ginkgoes are felt to be the link between ferns and flowering seed bearing plants.  

Unlike many other plants that have evolved in nature, the ginkgo has remained basically unchanged, probably thanks to the long cultivation by Buddhist monks.  Fossilized leaf material from270 million years ago is very much like the Ginkgo biloba of today.  That’s why Darwin called it a “living fossil”.  Botanists consider it a living wonder because it could be the oldest living seed plant in the world.

Ginkgoes are favored as a landscape and urban tree.  It’s a tough and durable tree with few insect pest or disease problems.  It’s also very resistant to pollution. It’s a hardy tree that does best in climates with wet winter weather and hot summers.  It does quite well in our region. The trees in Prosser are an example of their suitability for this area.

The tree itself is not especially pretty when young, but it does have an interesting growth pattern. As a young tree, it’s pyramidal in shape with a strong central leader.  Branches along this main trunk are regular, ascending, and asymmetrical.  The interesting growth of the ginkgo is due to its branching pattern.  The tree develops a combination of long and short branches that grow at right angles to the trunk and larger branches.  Its irregular growth pattern is attributed to the tips of larger branches sometimes becoming slower growing, shorter type of branches and the shorter side shoots changing to the faster growing, larger branches. 

The ginkgo’s unique bright-green leaves are produced alternately along longer branches and clustered at the tips of shorter side shoots. They’re two-lobed (“biloba”), fan-shaped, leathery, and smooth.  The veins fan out from the base of the leaf and aren’t cross-connected by smaller veins.  In the fall, the leaves turn a bright golden yellow and all drop off almost overnight with the first sign of cold weather.                          

The tree eventually grows to a height of 50 to 90 feet tall and 30 to 40 feet wide with a thick trunk, 13 to 30 feet in diameter.  Male trees generally have more of a columnar form, where females will have a somewhat wider crown.  As the trees age, they develop a wonderful grey bark with deep furrows.

Ginkgoes are a very durable tree.  Proof of that durability was found in Japan in 1945 after the atomic bomb was dropped on Hiroshima.  Human life was lost, buildings were obliterated, and plants were scorched and killed... except some ginkgoes survived.  Several ginkgo trees around the epicenter of the blast on a temple-site survived and resprouted without any visible genetic deformation.  Amazingly, two of these surviving trees still grow in Hiroshima today and are considered “bearers of hope”.

Remember that stinky fruit I mentioned earlier?  They look like yellow cherries and drop from the trees just prior to leaf fall.  It’s the fleshy outer covering that smells.  Inside a woody nut can be found. These nuts are a special food delicacy in China and Japan.

Today’s use of ginkgo leaf extract in a variety of natural medicines stems from its use in traditional ancient Chinese medicine.   The Chinese have used it to help with a variety of ailments.

It’s believed that ginkgo trees can live up to 3,000 years or more!  Ginkgo trees are honored trees in Asia where they have been seen as symbols of changelessness, unity, love, and hope and even possessing special miracle powers

Garden Note: If you want to plant a ginkgo tree, you may want to get a male tree.  They don’t produce stinky fruit, just the female trees do. However, female trees won’t usually flower or fruit until they’re about 20 years old!

Trees with Something Special

Trees with Something Special

Marianne C. Ophardt
Washington State University Extension
Area Horticulture Specialist

Not all trees are the same.  There are some trees with that “something special” that makes you want to plant them in your yard.  It might be beautiful flowers in the spring or summer, a different shape or overall form, brilliant color in the fall, or even outstanding bark.

When you plant trees and shrubs in your landscape, you’re painting a picture.  Good landscape designers, photographers, and artists all know that there should be a focal point in a picture.  The focal point directs the viewer where to look, creating a sense of depth and space. In landscape designs that focal point is often a tree with that “something special”.  Other landscape plants are used for balance and harmony in the picture.  No picture or front landscape design should have two focal points at one time.  It’s unsettling to the eye and creates disharmony.

In formal landscapes the focal point is often centered with the other elements of the design placed symmetrically to the left and right, mirroring each other.  While it’s easy to balance these types of landscape designs, they tend to be stiff and lack originality.  However, they work well with very formal styles of architecture. 

Asymmetrical landscape designs are informal and have more room for creativity and diversity in plant selection. Focal points are positioned off-center and other plants are carefully selected and placed to create balance.  Most home landscape designs are asymmetrical informal designs.

Knowing that the tree you plant with “something special” will be the focal point of your landscape, special care should be taken with its selection.  It’s easy to fall in love with a tree at the nursery or in a catalog, but you also need to make sure it’s suitable for your design and landscape conditions.  Here are some questions you should ask before planting a tree with something special.

What’s the Mature Size?

Find out its ultimate mature size.  It may look small and cute in the nursery, but just how big will it be when it grows up?  Will it fit where you want to put it in your design?  A focal point tree can grow to a size that’s out of balance with the rest of the landscape.

Is it Hardy Here?

Is it hardy in this region?   This region is generally considered to be located in Zone 6 on the USDA Hardiness Map. Plants hardy in Zones 7 or higher may grow well and survive our milder winters, only to die several years or more after planting when we experience colder winter temperatures that can be expected from time to time in this region.

Is it Suitable for Our Climate and Soils?

Will it withstand local soil and climate conditions? Most home landscape soils in this region are somewhat to very alkaline.  Some trees prefer acid soils rich in organic matter.  If a plant has to struggle to grow, it won’t likely become the attractive focal point you had anticipated.

Are there Any Troublesome Insect or Disease Problems?

Does it have any major pest or disease problems that could lead to continual maintenance problems or a short life expectancy?  A sick plant detracts from the landscape “picture” and may well be an unattractive focal point.

Is Suitable for the Site & Exposure?

Does your design meet the tree’s exposure needs?  Does it need protection from full exposure to sun and wind?  Does it need full sun or partial shade?  Select a tree suitable for the location where it will be planted.

Does It Create A Mess?

Does it create a litter problem with leaves, seed pods, fruit, or flowers?  If you want your landscape to be as “pretty as picture”, a tree that creates a lot of litter can detract from the picture you have created.

There are many trees available from local garden centers, nurseries, and mail-order catalogs that might catch your eye as that tree with some special characteristic that makes you want to take it home and use it as a focal point in your landscape design.  Here are a some trees you might run across on your search.

Weeping Trees

Weeping trees have a pendulous form that contrasts with the many other upright and spreading forms in a landscape design.  Their graceful hanging branches are poetry in motion.  There are both large and small weeping trees... be sure you know how tall and how wide the weeping tree you select will grow.

Double Weeping Cherry (Prunus subhirtella ‘Pendula Plena Rosea’) (25' x 25'). In addition to a graceful weeping form, the multi-seasonal interest of double pink flowers in the spring and yellow to bronze leaf color in the fall make this tree a wonderful focal point specimen.  This species of flowering cherry is longer-lived,  hardier and more heat and stress tolerant than many of the other flowering cherry species.  Two other weeping cherries are also worth consideration.  Weeping Yoshino Cherry (Prunus x yeodensis ‘Shidare Yoshino’) (12' x 15') with pink tinged white flowers and Snow Fountains Cherry (Prunus x ‘Snofozam’(12' x 12') with white flowers are smaller, but equally as graceful weeping flowering cherries.

Weeping Katsura Tree (Cercidiphyllum japonicum ‘Pendulum’) (25+’ x 20') Katsura trees are one of the most beautiful trees you can plant, especially in the weeping form.  The heart-shaped leaves are bluish-green during the summer and turn an outstanding yellow-orange in the fall.  The branches cascade to the ground evocative of a waterfall.  The bark of this tree is susceptible to sunburn if drought stressed or planted in high heat situations.

Young’s Weeping Birch (Betula pendula ‘Youngii’) (15' x 20') Many gardeners can’t resist a birch, especially one with white bark.  This weeping form is perfect as a focal point for gardeners with smaller landscapes that must have a birch.  It tends to grow asymmetrically giving it an interesting overall form.  It’s often grafted onto a standard stem creating a “mop-head” type of appearance.  Gardeners should be aware that it is susceptible to the bronze birch borer that decimates birch trees and is a serious problem in this region.

Weeping Beech (Fagus sylvatica ‘Pendula’) (50' x 60+') A large weeping tree that has an ascending trunk and is slow growing.  Weeping Purple Beech (Fagus sylvatica ‘Purpurea Pendula’) (10' x 15') is a much smaller tree with purple leaves and a dome-like crown.

Other weeping trees to consider include Emerald Cascade Honeylocust ‘Emerald Cascade’ (16' x 16') a honeylocust with dark green, fine textured leaves that turn butter-yellow in the fall; Chaparral Weeping Mulberry (Morus alba ‘Chaparral’) (12' x 16') a non-fruiting mulberry that’stolerant of heat and alkaline soils; Weeping Pagoda Tree (Sophora japonica ‘Pendula’) (15' - 25' x 15') unlike the species it produces few flowers; and Weeping Willowleaf Pear (Pyrus salicifolia ‘Pendula’) (15' x15') a weeping pear with gray-green, willow-like leaves.  There are also numerous glorious weeping crab apple trees, but they should not be grown here because they can become infested with codling moth and require regular spraying to help protect local commercial apple orchards.

Flowering Trees

Flowers, especially early spring flowers, can lead to love at first sight when the trees are in bloom.  However, blooms don’t last very long and it’s advisable that the tree have other characteristics that will make it the focal point of your design at other times during the year... such as fruit, fall leaf color, form, texture, or bark characteristics. The list of noteworthy flowering trees is very long. Here are a few you might want to consider.

Mt. Fuji Cherry (Prunus serrulata ‘Shirotae’) (15' x 20') You can’t wrong with a Japanese flowering cherry.  This one has a spreading form and pink flower buds that open to large double white flowers.

Kwanzan Cherry (Prunus serrulata ‘Kwanzan’) (30' x 20') The most popular of the double flower types of Japanese cherry.  It has rosy pink flowers borne in clusters, plus the leaves turn a nice bronze to orange color in the fall.  A very showy tree, but it’s susceptible to borers and cankers.

Vossii Goldenchain Tree (Laburnum x watereri ‘Vossii’) ( 25' x 20') This tree has an interesting vase shape and produces a spectacular display of rich yellow flowers in hanging clusters.  However, the tree is not very attractive when it’s not in bloom. Beware, the seeds are poisonous. 

Flowering Dogwood (Cornus florida) There are many cultivated varieties of flowering dogwood and hybrids with kousa dogwood or the Pacific dogwood.  The flowers range from pure white to creamy white to pink, deep pink, and ruby red.  The shape and size also vary from cultivar to cultivar, but all are relatively small trees less than 25 feet tall.  Flowering dogwoods prefer soil that is high in organic matter and acidic.  While these conditions are not found in most area landscapes, the trees will do quite well here if provided with adequate moisture, acidifying fertilizer, and organic mulch.  Many local gardeners find that flowering dogwoods perform best in a protected location and need pampering for the first several years before they become well established.

There are many other flowering trees, but none so durable and versatile as flowering crab apple trees and the flowering pears.  However, they’re not recommended for local landscapes because of the problem with codling moth.

Trees with Attractive Fall Color, Bark, or Leaves

As the growing season ends, the fall color of the leaves, the silhouette of the tree,  and the pattern of the bark are all characteristics that can maintain a tree’s position as a focal point. 

Here are some more trees to consider for fall color, form, or bark characteristics:

Red Maple (Acer rubrum) (40' -  45') The true red maples (not to be confused with Norway maples with purple leaves) just can’t be beat for their riotous display of brilliant orange to bright red leaves in the fall.  October Glory, Red Sunset, and Autumn Flame have some of the best fall color you can find.  October Glory is better adapted to areas like ours with hot summer temperatures.  During the spring and summer the leaves of red maple are green.

Empress Tree (Paulownia tomentosa) (40 '- 50' x 40' - 50') While this is a large, very messy tree, many gardeners who see it fall in love with its unique form, flowers, big leaves, and large seed capsules.  It’s a coarse tree with a dense rounded crown.  The pale violet flowers are produced in May.  In the fall the tree is covered with unique one to two inch persistent capsules.

Heritage River Birch (Betula nigra ‘Cully’) (40' x 30') Many local white-barked birches are succumbing to bronze birch borer, so if local gardeners want to grow a birch with interesting bark, this is one to try.  The peeling bark is a mottled mosaic of cream, orange, and tan colors. The leaves are large, glossy, and light green. 

Red Oak (Quercus rubra) (50' x 45') If you want an oak, pick this one. It tolerates local alkaline soil conditions and grows relatively fast, plus it’s dark green leaves turn a beautiful rich red in the fall.  This is a bit large as a focal point tree, but worth considering for larger homes and landscapes. 

RotundilobaSweetgum (Liquidambar styraciflua ‘Rotundiloba’) (45' x 25') If you’re looking for good fall color, the sweetgum will deliver.   The fall colors of the different cultivars range from spectacular burgundy red to orange to purple.  Rotundiloba has bright green glossy leaves with distinctive rounded lobes and it’s also fruitless.

Japanese Maple (Acer palmatum) The Japanese maple is a prized maple for creating focal points, especially in smaller yards.  This much appreciated and valued tree varies greatly in mature size and form.  While there are many weeping forms, there are also numerous upright cultivars.  Summer leaf colors vary from green to purple to red.  Many forms have lacy leaves.  Japanese maples are lovely specimen trees, but most won’t tolerate dry soil, low humidity, wind, intense sun, and high temperatures.  In this region Japanese maples need to be placed in a protected location, away from wind and hot afternoon sun.  They should be mulched with organic mulch and the soil must be kept moderately moist.

Trees to Avoid

Trees to Avoid
(Trees Which Are Often Used, But Have Serious Insect, Disease, Or Litter Problems)

Marianne C. Ophardt
Washington State University Extension
Area Horticulture Specialist

SYCAMORE (Platanus occidentalis) 75-100'. A very large tree which should not be planted except on the largest lots. Constantly dropping leaves, twigs, and seed clusters. Sycamore blight (anthracnose) is a serious disease problem. It appears to be very sensitive to injury from the herbicides 2,4-D and dicamba, even when used properly.

TREE OF HEAVEN (Ailanthus altissima) 40-60". This tree is adaptable to the most difficult of conditions but it is a course tree that tends to be very weedy. Should be planted only in impossible situations where nothing else survives.

SILVER MAPLE (Acer saccharinum) 50-120'. Another very large tree with a fast rate of growth. It tends to be a very weak wooded subject to many disease and insect problems. There are many superior forms of maple with many more desirable aspects. Has very little fall color. Roots are very invasive.

BOX ELDER (Acer negundo) 30-50'. This is another fast growing, weak wooded maple. It tends to be susceptible to many disease and insect problems. Very susceptible to verticillium wilt. The white variegated form has some merit. Short-lived tree.

POPLAR (Populus alba) 40-90'. This is an easy to grow "trashy" tree that continually drops leaves, twigs, and other debris. It is weak-wooded and tends to be weedy. Susceptible to many diseases and wood borers. Short-lived tree. Water seeker, invasive roots.

COTTONWOOD (Populus deltoides) 75-100'. Very large tree with all the problems of the preceding poplar. Water seeker, invasive roots.

PIN OAK (Quercus palustris) 60-70'. This is a good tree although there are many better oaks available, but it is intolerant of the alkaline soils encountered in this area.

WEEPING WILLOW (Salix sp.) 50-80'. A well loved tree but out of place in the normal home landscape. It is extremely weak wooded and very susceptible to aphids. The root system is very invasive.

RUSSIAN OLIVE (Elaeagnus angustifolia) 15-40'. Not the most beautiful of trees, but has a purpose in saline soils or where gray foliage is desired. It tends to be a rangy, weedy plant. Very susceptible to verticillium wilt, crown gall and aphids.

SIBERIAN ELM (Ulmus pumila) 50-70'. Does not deserve to be planted in the landscape. A shrubby tree with poor form. Brittle wood. Very susceptible to insects - especially aphids and the elm leaf beetle.

CRAB APPLE (Malus sp.) Crabapples are very nice trees but their fruit, large or small, are attacked by codling moth and apple maggot. Because these pests cause problems for local commercial apple growers, it’s not recommended to grow them in this region unless you intend to spray regularly with recommended pesticides to control these pests. In fact, it’s county law that you control these pests or remove your tree.

LAVELLE HAWTHORNE (Crataegus lavellei) 20-30'. A nice tree with lustrous deep green foliage and white showy flowers, but also should not be grown because it’s fruit are attacked by codling moth and apple maggot.

Why Sycamores Aren’t a Good Shade Tree for Most Home Landscapes

Why Sycamores Aren’t a Good Shade Tree for Most Home Landscapes

Marianne C. Ophardt
Washington State University Extension
Area Horticulture Specialist

The “true” sycamore is Plantanus occidentalis.  It’s also known as the American Planetree, Buttonwood, and Buttonball Tree.  This tree is native to North America.  It grows to a height of 75 to 100 feet.  Behemoth would be a good description of mature sycamores.  Sycamores are extremely susceptible to sycamore anthracnose (blight) and are also subject to problems with powdery mildew and sycamore lace bug. 

The London planetree (Plantanus x acerifolia) is commonly referred to as a “sycamore” in this our area, but it’s actually a different species.  It’s a result from a cross between the American sycamore (Plantanus occidentalis) and the Oriental planetree (Plantanus orientalis).  This London planetree is also excessively large, growing to a height of 70 to 100 feet.  This species is more resistant to sycamore anthracnose, but is still subject to the disease along with powdery mildew, sycamore lacebug, and the American plum borer.  There are several newer cultivars of the London planetree which are more resistant to anthracnose and should be considered when anyone decides to plant a sycamore.  

What’s good about the London planetree?  It’s a fast growing shade tree.  Unlike many other fast-growing shade trees, it’s not extremely weak wooded and thus isn’t prone to a lot of limb breakage in ice and snowstorms.  It’s easily transplanted and will do well in most soils, but prefers a deep, rich soil. It’s also tolerant of city conditions... air pollution, compacted soils, and drought.  It’s a very durable tree.  As a big tree, it also provides lots of wonderful shade in parks. 

Probably the most attractive feature of the tree is its bark.  As the tree matures, it sloughs or sheds pieces of the outer bark, giving it an interesting dappled pattern of olive green, cream, and light brown.   This random mosaic pattern is quite lovely and gives a special interest to the tree in winter.  If I was going to like the sycamore, it would be for its eye-catching bark. 

Now... on to it’s less desirable features.  One of the most obvious negative features is the size of the tree.  The London planetree is a BIG tree!  It grows to gargantuan proportions and is not well suited to the typical home lot or along a city street.  Growing to at least 70 feet or more in height and 80 feet or more in width, you need plenty of room for a London planetree.  Planted in the wrong place it can quickly come into conflict with utility wires, sidewalks, and driveways. Keep in mind that roots go out at least as far out from the tree as the tree is tall ... or more.

Because of its size and the lack of forethought when planting this tree, many tree owners opt to butcher their “sycamore” with topping or severe pruning when it gets too large for its space.  This pruning shortens the life of the tree and results in lots oftwiggy growth.  Attachment of this growth is weak, creating a hazard as the resulting branches grow larger and heavier.  Numerous fallen branches are often the consequence of windstorms and past topping of the tree. Open topping wounds lead to eventual wood rot.

Another problem with sycamores are their susceptibility to sycamore anthracnose , also known as sycamore blight.  This is a fungus disease that attacks sycamore buds, leaves, and shoots. The most typical symptoms are small to large brown dead areas along the main veins of leaves. Severe infections lead to leaf drop.  Infections in twigs and branches cause twig dieback. 

Cool, wet springtime conditions favor anthracnose development on sycamore. The disease is more severe when we experience a spring like we encountered this past April and May.  While it’s not “normal” for us to have repeated precipitation during the spring, it seems to be a frequently occurring weather pattern during the past five to ten years.  A disease that shouldn’t ordinarily be a problem with our “normal” climate, has continued to attack and disfigure area sycamores.  Repeated attacks seldom kill a tree, but they can sure give it a rather ugly, witches-broom or bushy appearance.

Fungicide applications to control the disease can be made early in the season when the buds swell and again when the bud caps begin to break.  However, control is often difficult because of the large size of the tree and the difficulty in getting good coverage. 

Powdery mildew is another disease problem that has been infecting some area sycamores.  It causes a distinctive white powdery fungus on upper leaf surfaces and green shoots. Leaves, especially those at the ends of branches, may be dwarfed, twisted, and completely covered by the fungus. The disease is usually worse on severely pruned trees which have lots of succulent leaf and twig growth. The powdery mildew usually becomes evident in late summer or early autumn.  Little real damage actually occurs to the trees other than the deformity of the leaves.  Control with applications of fungicides is not warranted unless the tree is of very high value or in a location where it serves as a focal point.  

As already mentioned, there are anthracnose resistant cultivars of the London planetree (a.k.a. sycamore.)  One cultivar, `Yarwood’ is very resistant to powdery mildew and fairly resistant to anthracnose.  ‘Bloodgood’ is very resistant to anthracanose.  `Liberty’ and `Columbia’ are two other cultivars that have been touted as being anthracnose resistant, but they’re apparently only resistant to eastern strains of the disease and not western strains. 

One of the positive features of sycamores planted in our area is that they aren’t often attacked by insect pests.  However, one little creature seems to be on the rise.  It’s the sycamore lacebug.  The lacebug is a tiny creature with clear lace-like wings.  It sucks the sap from the undersides of leaves causing astippled or speckled appearance on the top of the leaf.  The lacewings leave shiny black spots of excrement on thelower leaf surface. 

Visible damage from the lacebugs only seems to become evident late in the season.  In most cases it should not seriously harm the trees.  Trees should be kept in a vigorous condition with proper cultural care.  Stressed trees are more susceptible to attack and damage.  It’s especially important not to drought stress the trees during hot weather.  If control with a pesticide application seems necessary, an application of insecticidal soap would provide some control and still protect many of the natural predators.

Finally, this is a messy tree. Because the leaves are so large and numerous, they ’re a real nuisance in the autumn.  Add to this the litter from the numerous seed balls and twigs shed by the tree and you have a persistently messy tree.  In conclusion, it’s not advisable to plant a sycamore... but if you must, plant a resistant cultivar of the London planetree and be sure you have plenty of room for it to grow.

Good Trees for Fall Color

Good Trees for Fall Color

Marianne C. Ophardt
Washington State University Extension
Area Horticulture Specialist

What are some trees that will grow well in our area and provide consistent fall color?  If you’re looking for a bright red to purple, look for an American sweetgum (Liquidambar styraciflua) tree.  They hold their leaves until late in the fall and provide an excellent display.  Look for selected cultivars, such as `Moraine,’ which has a very bright red fall color.  `Moraine’ also has a relatively fast rate of growth.  Sweetgum prefers an acidic, moist, rich soil and will need some special attention in area landscapes where the soil is very alkaline ... but it’s worth the trouble.  Sweetgums are relatively pest free ... another plus on their side.

The red maple (Acer rubrum) is another colorful autumn tree.  It does very well in area landscapes and tolerates a range of soils and conditions.  Its fall color ranges from yellow to orange to fiery red, depending on the cultivar.  While there are many, many cultivars, `October Glory’ and `Red Sunset,’ are two local favorites.

Other trees that provide spots of red, bronze, purple, or yellow fall color include flowering pear, flowering dogwood, red oak, Norway maple, Japanese maple, gingko, aspen, and birch. If you long for more fall color in this area, plant some of these trees and shrubs and encourage others to plant them too!

Uncommon Trees to Try

Uncommon Trees to Try

Marianne C. Ophardt
Washington State University Extension
Area Horticulture Specialist

It's easy to find Norway maple, red maple, flowering pear, sweetgum, poplar, or sycamore trees in many local landscapes, in our parks or along the city streets.  Many are familiar friends that we know by name, but what about some of the less familiar trees that we don't often find in this area?  Let's take a look at a few you might want to consider if you ever run across them in a nursery.

One interesting tree is the Japanese Pagoda Tree, also known as the Scholar Tree (Sophora japonica).  This is a distinctive tree and should be considered as a specimen shade tree.  It grows to 75 feet tall.  It's has a dense upright crown when young, but becomes spreading and broadly rounded as it matures. It has a moderate rate of grow until it reaches the height of 20 to 30 feet and then it grows very slowly.

One of it's best features is its shiny, bright green compound leaves which turn yellow in the fall.  While the compound leaves are fairly large... 6 to 10 inches in length... they break apart in the fall and don't need raking. The tree is a good one for providing filtered shade.

Another distinctive feature of the Pagoda Tree is its flowers which form in late summer... long after most other flowering trees.  The flowers are wisteria-like hanging clusters of creamy-white, somewhat fragrant blooms. These form 3 to 8 inch pods in the fall.

This tree has few pest and disease problems. Once it becomes established, it's fairly tolerant of heat and drought.  The biggest drawback is the yellow staining that may occur from the fallen pods... so don't plant them near a paved surface.  They also take about eight to ten years before they flower, however the cultivated variety `Regent' tends to flower after about six years.

While the Amur Corktree (Phellodendron amurense) probably wouldn't be considered as lovely as the Pagoda tree, it is a tough tree.  With a medium growth rate, it reaches a height of 30 to 45 feet at maturity with a spread to match.  It has few pests and is tolerant of alkaline soil and drought conditions.

The leaves are a glossy green turning a yellow or bronze in the fall. The flowers are an unremarkable yellow-green.  The most attractive features of the Corktree are its overall texture and its bark.  Its short trunk, twisted limbs, stout twigs, and large compound leaves give it an overall coarse, rugged appearance.  As the tree matures the corky bark becomes ridged and furrowed, creating an attractive and interesting pattern. This broad spreading tree should be considered, but only for large lots and park-type areas.

The Katsura Tree (Cercidiphyllum japonicum) should be deemed a great tree on its beautiful fall color alone.  It is a tree though that will need more pampering in our area than the other trees mentioned so far.  The Katsura tree grows to a mature height of 40 to 60 feet with a medium rate of growth.  Its crown is full and dense, changing from a pyramidal form when young to a more spreading form at maturity.  However, some trees maintain their upright form into maturity.

The delicate, heart-shaped leaves are the best feature of the tree.  They emerge in the spring with a reddish-purple color, changing to a dark blue-green in the summer, and then to an unmatched apricot-orange in the fall. 

In other areas this tree does fine in full sun, but in our area it will need some protection from hot sun and dry winds. It can also have problems with sunburn on the bark.  It prefers a moist, well-drained soil which is high in organic matter.  This tree doesn't like drought and should be watered carefully to avoid water stress in the hot periods of summer.   Mulch with an organic mulch, such as compost or shredded bark.  Protect the bark of young trees from full sun.  It has few pest problems. 

If you are looking for a magnificent small tree you might want to weigh the merits of Japanese Stewartia (Stewartia pseudocamellia). Here's a tree that grows from 20 to 40 feet in height at maturity and has a pyramidal to upright-oval shape.  As the Latin name implies, the flowers look like little camellias.  These white flowers with their gold-orange centers are produced in late summer over a fairly long span. 

The leaves are a dark green in the summer turning to various shades of deep red and purple in the fall.  The sinewy bark is another desirable feature of the tree.  As the tree matures, the bark flakes off in patches creating an interesting pattern of cream and tan.

This tree doesn't seem to have a lot of pest problems, but it also needs pampering in our area.  It prefers an acid, moist soil which is high in organic matter.  It should be protected from hot sun and wind.  Be sure to mulch with organic mulch.

Finally, the Chinese or Lacebark Elm (Ulmus parvifolia)is a good, tough medium-sized tree that will most likely be admired for its unusual bark.  Don't confuse this with the weedy Siberian elm (Ulmus pumila) which pops up here and there of its own accord.  The true Chinese or Lacebark elm is much different and much better.  First of all, it’s resistant to elm leaf beetle and Dutch elm disease.  It grows to a height of 40 to 50 feet with a medium to fast rate of growth.  The tree is tolerant of alkaline and poor soils.  However, it does prefer moist, well-drained soil.

The small leaves are a shiny dark green. The bark is wonderful... a mottled pattern of gray, green, orange, and brown.  There are a number of good cultivated varieties available. Depending on the cultivated variety, it develops a graceful rounded crown or an upright spreading form.  If you like the vase shape of the American elm, look for `Emerald Vase' an excellent cultivated variety with an upright spreading form.  `Emerald Isle' is another excellent variety with a more rounded type of crown.  Both are highly resistant to the elm leaf beetle and Dutch elm disease.

Ginkgos Are Living Fossils

Ginkgos Are Living Fossils

Marianne C. Ophardt
Washington State University Extension
Area Horticulture Specialist

Did you know early in the last century petrified Ginkgo biloba (pronounced GINGK-go bi-LO-ba) logs were uncovered near the Columbia River in Central Washington?  It's believed that ginkgo trees once formed large forests in this area ... over 30 million years ago.  They were preserved by sediments and lava flows that occurred in the Central Washington area.

Jack Hampton, Washington State University Master Gardener, was a nut and fruit enthusiast who passed away in 1999.  He was a local expert on nuts.  Hampton said that, "Most people don't recognize ginkgo trees as nut trees, but they are actually the world's oldest cultivated nut.  At present Ginkgo trees probably don't exist anywhere as wild trees, but 150 million years ago, during the Mesozoic era, they enjoyed widespread distribution throughout the northern temperate zone.  At this time there were dinosaurs, marine reptiles, pterodactyls, ammonites, ferns, and gymnosperms (plants with naked seeds not enclosed in a fruit) inhabiting the earth. Mammals, birds, and angiosperms were just beginning to appear. Angiosperms are basically flowering plants (with seeds enclosed in a fruit.)  The ginkgo is the only non-extinct gymnosperm that has seeds that are not produced in a cone.  They are a living fossil!"

There have been many fossils of the characteristic ginkgo leaves found from the Jurassic and Triassic Periods (135-210 million years ago) when dinosaurs roamed the earth.  The ginkgo forests in North America were wiped out long ago by catastrophic geological and environmental activities, such as floods and the ice age.  So how come do we still have living ginkgo tree around today?   The Ginkgo survived the Ice age because the sheets of ice didn't reach parts of southeast China.  Ginkgoes were able to survive the ancient forces of nature and were later cultivated in temple gardens for centuries by Chinese monks.   All the living ginkgoes that are around today are descendants of these Chinese ginkgoes. 

It's easy to identify a ginkgo tree with its unique, fan shaped leaves.  They haven't changed much in 200 million years!  Ginkgo trees are either male or female.  Hampton notes that the "female tree bears a plum-sized fruit that has a disagreeable odor when ripe.  The pulp may also cause an allergic dermatitis and contact with the skin should be avoided." The odor of the fruit has been compared to rancid butter and dog manure, but I think it's much worse.  Watch out if you step on one... they are odoriferous little land mines.    Hampton wonders what types of animals fed on these to spread them throughout the world in prehistoric times...  obviously ones without a refined sense of smell!

Most people try to avoid planting female ginkgo trees so they can avoid getting these attractive yet stinky fruit.  Unfortunately, sometimes they end up with female trees even though they were supposed to be the non-bearing male trees.  Oops!  You will find a few female Ginkgo trees growing in this area and if you are the curious sort you might want to know how to harvest the nuts.  Hampton offers these tips on harvesting Ginkgo nuts, "Gather the ripe fruits using rubber gloves.  Squeeze out the seeds in a bucket of water, wash them thoroughly, and then dry them.  The result will look like a large unsplit pistachio nut.  They are not ready to eat at this point.  To prepare them for eating, first crack them with a pair of pliers.  Then boil them for about ten minutes.  The inner skin (called a pellicle) will fall off leaving a light yellow kernel.   It's this kernel which you eat.  It tastes something like sweet corn.  You may keep these nuts in your refrigerator in plastic bags for a short time, but they are highly perishable."  Hampton noted that the "Chinese have long eaten these white nuts on special occasions, such as weddings and holidays."    He also cautioned that those new to eating Ginkgo nuts observe caution with this new food.  Eat it only in small quantities until you have determined that you have no allergies to the nuts.

If the opportunity to have a living fossil in your own yard intrigues you, you'll be happy to know that you can grow a ginkgo tree quite easily in this area.  Hampton pointed out that ginkgo trees are hardy, adaptable trees that grow in a wide variety of soils and climates.  They are tolerant of drought and urban air pollution. 

As a young tree, a ginkgo has an upright, irregular pyramidal form, and become broader, and more symmetrical with age.  It reaches a height of 50 to 80 feet at maturity. It grows relatively slowly.  Ginkgo trees are remarkably free of pests and disease problems and quite reliably develop wonderful yellow-gold fall color.  They do best if planted in a well-drained, sunny location.  It does take them a while to recuperate after transplanting.

One special thing to remember when you purchase your tree is that you want a male tree.  Remember the ginkgo is dioecious, meaning there are separate sex trees.  You'll have to take the nurseryman's word for it though... as it takes about twenty years before they start bearing nuts.  There are several selected cultivated varieties that you may want to look for in the nursery.  They are 'Autumn Gold' (a male with a broad, spreading form), 'Pendula' (with branches more or less pendulous), 'Shangri-La' (fast growing with compact form), and 'Princeton Sentry' (an upright form, male.)

Whose Tree is it Anyhow?

Whose Tree is it Anyhow?

Marianne C. Ophardt
Washington State University Extension
Area Horticulture Specialist

What would Robert Frost have said about the controversies some neighbors have with trees that border their properties?  After all, he addressed the problems of neighbors putting up fences in his poem, “The Mending Wall.”  The truth is that some folks just don’t get along.  Some people reasonably take exception to leaves from a tree they don’t own blowing into their yard or dropping into their pool, especially if there is a large volume of leaves that they must clean up and dispose of in some manner.  Controversies arise over roots growing into yards and gardens from an adjoining tree, or sometimes the tree gets large enough that it actually grows over the lot line even if it started out on one side of the lot line.  Who’s responsible for a tree planted on the lot line?  This question can cause quite a bit of acrimony. 

There are also increasing numbers of controversies over trees which block panoramic views, especially in Western Washington where housing has become increasingly dense and people pay premium prices for select view lots.  Imagine having paid that extra money for your view and then your neighbor plants a tree and it grows up and blocks your view.  There are stories about people hiring arborists and having them come and cut off the tops of offending trees while the owners are away.  Of course, you can imagine that this causes more than a mild argument.  Arborists are finding that they have to be very careful in finding out about who actually owns the tree they are being asked to prune.

It used to be thought that you could do just about anything you wanted to any part of a tree that encroached upon your property... whether it was limbs overhanging your side of the fence or roots causing havoc on your side of the lot line.  However, current conventional legal wisdom seems to protect trees from wanton acts by not-so-neighborly neighbors.  The following was written for the Washington State Department of Natural Resources “Tree Link” newsletter by Mark C. McPherson, of Hillis Clark Martin, & Peterson, P.S. and appears here with permission.

1.  Trees Have a Dollar Value That Can Be Appraised

We all know that trees are pleasant to have around, and that they reduce pollution, add oxygen to the atmosphere, buffer light and noise, and provide welcome shade in hot weather.  You may not be aware that there is a detailed appraisal formula that yields dollar figures for trees.  The International Society of Arboriculture developed an appraisal method that takes into account a tree's condition, location, species, and other factors to produce a dollar value.

The value may surprise you.  In a recent case handled by our law firm in Island County, nine medium-sized alder trees were appraised at almost $4,000.  Mature hardwoods such as oak and maple can be worth in excess of $5,000 apiece.

2.  Washington Law Allows Treble Damages For Willful Tree Cutting

Washington State in general does not allow punitive damages, but there is an exception for willful tree cutting on someone else's property.  The courts have awarded treble damages in cases where tree cutters have failed to make a diligent effort to ascertain the property line.  Anyone contemplating tree cutting should be sure to determine their property line before taking down any trees.  Anyone whose trees are cut should be aware that the damages may be far more than they imagined.

3.  Trees on Boundaries Are Jointly Owned

Suppose you plant a tree on your property, and over time the tree grows into the property line between you and your neighbor?  Washington law deems that tree to be jointly owned by you and your neighbor.  You cannot cut that tree down without getting permission from your neighbor.  Conversely, your neighbor cannot cut down trees on the property line without your permission.  An increasingly common situation involved branches or roots that extend from one property onto another property.  Washington law provides that these can be trimmed back to the property line.  However, recent legal decisions in California and British Columbia have held that a property owner cannot unreasonably damage the health of a tree by pruning back to the property line.  The law is becoming increasingly protective of trees, particularly in urban areas.  Property owners who damage a tree that appears not to be causing them any harm may have to pay for the damage.

4.  Subdivision Covenants Often Pit Tree Owners Against Those Who Want To Preserve Views

As property values go up, the value of views increases.  This has caused some property owners in certain subdivisions to sue to remove trees under restrictive covenants.  Covenants often contain provisions that are protective of views.  Even if covenants do not contain a specific view covenant, they may prohibit "noxious" or "undesirable" uses, which some subdivisions have interpreted to include view-blocking trees.  These disputes usually depend on the unique facts in each situation, but property owners who are protecting their views have turned to covenants to force neighbors to prune or remove trees.

The increasing value of views has also led some subdivisions to undertake "view zoning."  View zoning attempts to plan for specific vegetation in specific areas.  Large trees may be allowed in certain areas but prohibited in designated view corridors.  This preserves the visual and ecological appeal of graceful mature trees while limiting the haphazard impact on views.

5.  You May Be Responsible For Hazardous Trees on Your Property

Are you liable if a tree on your property falls and injures someone?  This depends on whether you knew or should have known that the tree posed a hazard.  If the injury was due only to an act of God, such as a lightening bolt striking a safe, healthy tree, you will probably not be liable.  But if your tree was diseased or had dead branches, a court may find that you should have known that the tree was hazardous.  This is particularly the case in urban areas where the risk of injury is greater than rural areas.

Buying Quality Trees for Planting in Your Landscape

Buying Quality Trees for Planting in Your Landscape

Marianne C. Ophardt
Washington State University Extension
Area Horticulture Specialist

Before buying a tree to plant in your landscape, make sure it’s a healthy, high-quality plant.  Whether you shop for your trees and shrubs at a local nursery or at a discount store, you should keep in mind that the plant is not only an investment of money, but also of time.  Don’t waste your time or money on a plant that will not grow well or will become a liability with time.

Some bargains aren’t really a bargain.  That’s why the International Society of Arboriculture advises, “When you buy a high quality tree, plant it correctly, and treat it properly, you and your tree will benefit greatly in many ways for many years.  When you buy a low quality tree, you and your tree will have many costly problems even if you take great care in planting and maintenance.” The International Society of Arboriculture, or “ISA” for short, is a non-profit organization supporting tree care research and dedicated to the care and preservation of shade and ornamental trees.

So what determines if a tree is high quality or low quality? It’s the condition of the root system, trunk, and framework of branches.  A high quality tree is one with an adequate root system for the tree.  The container should be large enough to accommodate the roots without circling roots forming on the outside of the root ball.  Roots that are circling, kinked, or entwined will continue to grow that way.  This usually leads to future problems when the roots eventually choke or “girdle” each other as they grow.  A few circling roots can be cut with a sharp knife and loosened, but low quality plants with a tight mass of circling woody roots should be avoided.

If a root ball is dug and wrapped in burlap (balled and burlapped) there should be enough of a root system to support the tree.  A rule of thumb used in the nursery industry indicates that the diameter of the root ball should be at least ten to twelve times the diameter of the trunk, as measured six inches above the trunk flare.  The “flare” is the area at the base of the tree trunk that curves outward.  It’s where the roots meet the trunk.  When purchasing a balled and burlapped tree, you should be able to see the flare on the trunk and the top of the root ball should be flat, not mounded and covered with bark.

After you get the tree situated in the planting hole, with the top of the root ball at the same level as it was growing in the nursery, you’ll want to cut all the twine off the ball and carefully pull back the burlap.  Remove the burlap by cutting, being careful not to disturb the soil ball surrounding the roots.   A plant with many major roots crushed, cut, or torn is poor quality.  This will greatly affect the tree’s ability to grow.   A plant is also low quality if it lacks enough roots to help hold the root ball together.  This type of tree will have severely restricted growth too.  However, even a high quality plant may have a few damaged major roots.  Use sharp pruning shears to make clean cuts on the injured roots.

A quality tree will also have a trunk free of wounds that are the result of poor pruning cuts or physical injuries to the bark.  ISA warns that there are often injuries or problems concealed by trunk wraps.  “Never buy a tree without thoroughly checking the trunk.”  Problems include poor pruning cuts that leave stubs that won’t “heal.” These can lead to disease and structural defects.  Older pruning cuts should show a ring of callus tissue that has covered the area of the cut.  These cuts are made just outside what is called the branch collar.  If branches are removed with flush cuts, the wound won’t cover over as quickly and can lead to cankers, trunk cracks, or wood decay.

Trees should also have a good, strong basic framework of branches.  If the framework hasn’t been well developed in the growing nursery, you won’t be able to correct significant structural defects with pruning.  The branches on a tree should be evenly spaced along the central leader.  According to the ISA, trees that have branches that are “squeezed” together should be avoided.  “Squeezed” branches are where you have two main branches or leaders arising from the same point.  As these leaders grow, they “squeeze” each other.  The older and larger the tree gets, these leaders often split apart.  Squeezed branches can’t easily be corrected by pruning, especially the larger a tree becomes.

You also want branches with strong attachments, ones that aren’t “squeezed” to the trunk.  When the angle of attachment between the branch and the trunk is less than 45 degrees, this is considered a weak attachment prone to cracking and breakage.  If you’re buying a fairly large specimen, examine the branches and look for small cracks that may already have formed at their bases.  A small crack can later develop into a larger one and lead to branch breakage.

Let’s review.  When buying a tree... you should look for a one with an adequate, healthy root ball.  The trunk should be free of defects and the branches should be well placed along the trunk.  Trees can be a significant purchase.  Take the time to inspect the tree you’re buying.  Inspect the trunk for defects and assess the branch placement and attachment.

Inspecting the root ball is trickier.  While I know a horticulturist who recommends removing a tree from its container right in the nursery, most nurseries won’t like you doing this.  You certainly can’t look at the roots of a balled and burlapped plant at the nursery without causing all sorts of problems.  I recommend checking the roots immediately when you get the plant home.  It’s easy to check the roots of a container grown tree or shrub.  However, balled and burlapped specimens should first be situated in the planting hole and ready to be planted before removing the burlap. 

Some nurseries will recommend leaving the burlap on the root ball.  They will not guarantee their plants if you remove the material.  However, Mid-Columbia Community Forestry Council members have observed too many problems, such as a lack of roots and severe damage to the root system, beneath the burlap to be comfortable with leaving it on.  The burlap also usually doesn’t rot quickly enough in our climate and frequently restricts root and tree growth.  The fact that burlap is often treated with copper to keep it from rotting is also a factor in restricting roots.  Copper retards root growth.  I recommend removing the burlap.

Big Trees Still Needed for Our Landscapes

Big Trees Still Needed for Our Landscapes (written in 2001) 

Marianne C. Ophardt
Washington State University Extension
Area Horticulture Specialist

Where have all the big trees gone? In 15 to 20 years that’s a question many people will be asking. For decades, large trees have created a feeling of well-being and comfort in many communities.  Area residents who have migrated to this region from other parts of the country can probably recall city streets that were lined with large trees. Where I grew up in Rochester, New York the streets were graced with sugar maples, elms, and Norway maples.  Large trees give you a “feeling of place” and help define the character of an area. 

We need not look elsewhere for another example.  Just drive down the older residential section of Kennewick Avenue, which is lined with large trees.  They provide a graceful ambiance to the area even though most of these trees are in poor health due to restricted roots, wood rot, and years of stress.  Driving down a street like this, you’re likely to relax a little and envy the people who live there.

This summer I visited the neighborhood where I grew up.  There were fewer trees along the street and in front yards.  Many of the older trees that had been growing there had been removed and not replaced with similar large species. The neighborhood was stark and much less hospitable.   I also visited the area that I later moved to as a teenager.  It had been a newer housing development with no large trees, only new plantings.  After thirty years, those small trees have grown into big trees.  The area was lovely and the homes seemed much more attractive and welcoming.  Can you think of a street lined with big trees and how it feels to walk or drive down it?

The Problem

So why will people in 15 to 20 years be asking where all the big trees have gone? One main reason is our choice of tree species.  Campaigns to plant the “right tree in the right place” have sound reasoning behind them. Utility companies have logically recommended using smaller trees when planting near or under utility lines.  To decrease the costly pruning required to keep wrongly planted large trees from growing into the lines and to help avoid losses of service from fallen trees and broken branches, planting smaller trees in the right place makes a lot of sense.

You shouldn’t plant a large tree, like a sycamore or a red oak, under utility lines, but there are“right places” for large trees in many of our residential landscapes.  Unfortunately, they’re seldom being planted.  With the demand for “instant” landscapes and the desire for fast growing trees, species that grow more slowly and become very large over a span of many years aren’t often selected.  That’s a shame.  Most of the faster growing trees species, such as poplars, don’t survive much past 15 to 20 years.  As these newer communities age, many of the faster growing trees will begin to decline and die.

Numerous cities have cut down unhealthy large older trees that posed a hazard to residents and traffic.  Large trees have also been removed to allow for growth and expansion.  Responsible cities have made commitments to replace removed trees... and to plant trees along new streets in residential and business developments.  Considering the maintenance problems that large, older trees caused... uprooting sidewalks, pruning for vehicle clearance, leaf removal, pest management and more,  cities have looked for “small” trees with narrower forms to plant along their streets and avenues.  While these trees do have merit, they won’t provide big trees for the generations to come.  Our children and grandchildren will not be able to enjoy the distinctive beauty of large, old trees and their contribution to our communities.

The Solution

So what’s the solution?  We can’t ignore the definite and sensible need of utility companies and cities to avoid the problems that large trees can create.  However, we do need to consider where we can plant large trees and how to plant them correctly to avoid potential problems in later years.  Communities should budget adequate money not just for planting trees, but also forpruning and tree health.  It’s relatively inexpensive to plant a tree, it costs a lot more to keep it healthy for the years to come.

If you like trees, there are two things you can do to help insure that there will be large trees for future generations.   First, encourage your community to plant big trees in suitable situations. Support tree care budgets... trees don’t take care of themselves.

Second, consider your own landscape, and see if a large tree might fit somewhere where it won’t interfere with utility wires.  Be sure to consider how tall and how wide the tree you’re planting will become at maturity.  If possible, plant the tree where your house will benefit most from the shade in the summer, but be careful not to plant it too close to the structure.  Remember the mature size.  Select a tree that doesn’t typically have major insect or disease problems.  There are no “pest free” trees, but there are more troublesome trees you should avoid.

Here are some of my top picks for big trees to grow in our area.

Big Trees to Consider

Red Oak (Quercus rubra) grows to 75 feet tall.  It grows relatively fast compared to many other oaks, but still it’s not a fast growing tree.  It has attractive deep red fall color and has relatively few pest or disease problems.  It’s also more tolerant of our alkaline soil conditions than pin oak, which should not be planted here.  It has attractive furrowed bark.  You can see some older red oaks at the Benton County Courthouse in Prosser.  These large red oaks have been around for many years and are still beautiful trees.

Red Maple (Acer rubrum) grows to 70 feet tall.  This tree has become quite popular because it’s tolerant of a variety of soil conditions including compaction, poor drainage, and excess water.  It’s a good durable tree with spectacular orange and red fall color.   You can observe young red maples in many area landscapes and parks. They’re one of my favorites and apparently a favorite of many other gardeners too.  Don’t plant silver maples that grow very fast.  They have weak wood, invasive roots, and no significant fall color. 

Japanese Zelkova (Zelkova serrata) grows to 80 feet tall.  It’s an attractive tree with a vase-like growth habit and ascending, arching branches, similar to elm trees.  It’s in the elm family, but it’s supposedly resistant to Dutch elm disease and elm leaf beetles.  It’s tolerant of alkaline soils, and once well established it will also withstand windy and dry conditions.  There is one of these on the grounds of the Tri-Cities Country Club. Look for ‘Spring Grove’, ‘Green Vase’, ‘Halka’, or ‘Village Green’.  Certain cultivars have moderate fall color.  This tree is not extremely common and may be difficult to find locally.

Sweetgum (Liquidambar styraciflua) grows to 75 feet tall.  When young, it has a pyramidal shape, but grows into a tree with a more oval or rounded crown.  The leaves are thick, glossy and dark green in the summer, turning to brilliant reds and purples in the fall color.  The root system will be extensive and needs lots of room to grow, so don’t plant them where there is limited soil or space for roots to grow.  The seed “balls” produced by the tree can be quite messy, but there are some cultivars available that produce only limited amounts of the balls.  Be aware that there are many different cultivars with varying forms including columnar, shrubby, and shorter forms.  Sweetgums are commonly planted in our area.  You can see an entire row running along a side walkway next to the main parking lot at the WSU-Tri-Cities campus in Richland.

London Planetree (Plantanus x acerifolia) grows to 100 feet tall and 80 feet wide or more.  It is a BIG tree!   Often called a “sycamore” it is actually a cross between a sycamore (Plantanus occidentalis) and the Oriental planetree (Plantanus orientalis).  It’s advantages are that it’s fast growing, long-lived and has few insect pest problems.  It’s tolerant of alkaline, compacted, and droughty soils.  It also has attractive flaking bark with a mosaic pattern.  It’s disadvantages include abundant very large leaves, the tree’s very large size, its prolific seed balls, and it’s susceptibility to sycamore anthracnose.  Two cultivars, ‘Bloodgood’ and ‘Yarwood’ are the best candidates for selection because of their resistance to anthracnose.  While I may have disdained this tree in the past, I have to say it’s a very durable tree and tolerant of harsh conditions and poor care, but please plant it only where it has plenty of room to grow and only plant the anthracnose resistant varieties.

Other large trees worthy of consideration include beech (Fagus sylvatica) silver linden (Tilia tomentosa), English oak (Quercus robur), littleleaf linden (Tilia cordata), and river birch (Betula nigra). 

Do Black Walnuts Poison Other Plants?

Do Black Walnuts Poison Other Plants?

Marianne C. Ophardt
Washington State University Cooperative Extension
Area Extension Agent  

Black walnut leaves, husks, and bark have been rumored to be toxic and not good for use in gardens and compost piles.  The start of this rumor comes from the phenomenon of certain types of plants wilting and dying when growing in close proximity to black walnut trees.  This is called “black walnut toxicity” or “walnut wilt.’ This phenomenon is not new.  In fact, it was noted by Pliny in Roman times.

Scientists have determined that there is a plant chemical called juglone that causes black walnut toxicity.  The largest concentration of juglone can be found in the buds, hulls, and roots of black walnut trees, but it’s also found in the leaves, bark and stem tissue.

Juglone is toxic to many other plants.  Black walnut toxicity primarily occurs when the tree’s roots exude juglone.  Juglone sensitive plants with roots in close proximity to the black walnut roots are affected.  Scientifically, juglone inhibits respiration, denying plants the energy they need for plant growth and metabolism.  Plant responses range from sudden wilt and death to stunted growth.  There are other members of the walnut family, such as Persian walnut, butternut, pecan and hickory, which also contain juglone, but don’t seem to produce it in sufficient quantities to produce toxicity symptoms.

There are a good number of black walnuts grown in this region.  Some area gardeners have been concerned about using the leaves and hulls in their compost because of the rumored toxicity.  According to an Ohio State University Extension factsheet “walnut leaves can be composted because the toxin breaks down when exposed to air, water and bacteria.  The toxic effect can be degraded in two to four weeks.  In soil, breakdown may take up to two months.  Black walnut leaves may be composted separately, and the finished compost tested for toxicity by planting tomato seedlings in it.” 

However, fresh sawdust, shredded leaves, or wood and bark chips from black walnut should not be used for mulching plants sensitive to juglone.  According to the Ohio factsheet, composting the bark for a minimum of six months provides safe mulch even for plants sensitive to juglone.

While rain may leach juglone from leaves and hulls, the juglone is highly reactive and quickly inactivated in the soil.  Juglone is also poorly soluble in water and doesn’t move very far in the soil.

Juglone sensitive plants include apple, asparagus, azalea, birch, blueberry, cabbage, ornamental cherry, chrysanthemum, crabapple, eggplant, lilac, linden, saucer magnolia, narcissus (some,) pear, peony, pepper, petunia, pine, potentilla, rhododendron, tomato, and more.

Ohio reports that problems with black walnuts are not limited to plants.  Horses may be affected by black walnut chips or sawdust when they’re used for bedding material.  Allergic symptoms in both horses and humans may also be produced by close association with walnut trees while their pollen is being shed in the spring.

Small Trees for Home Landscapes

Small Trees for Home Landscapes

Marianne C. Ophardt
Washington State University Extension
Area Horticulture Specialist

Plant small trees.  Of course, most trees are relatively small when planted in the home landscape, but only “small” trees stay a reasonable height for the normal home landscape. According to Dr. Ray Maleike, WSU Extension Horticulturist, smaller trees generally require less care than larger trees.  He says, “Small trees can be chosen so that they remain in bounds, have multi-seasonal interest, and are hardy, resistant to pests, and drought tolerant.”  He points out that when small trees do need care, such as pruning, irrigation, fertilization and spraying, the task is much easier because the tree isn’t so tall.

Larger trees also often create problems with their root systems.  The roots of larger trees tend to be more invasive, causing problems with sidewalks, driveways, and lawns. It’s prudent to note that the roots of a tree frequently extend as far from the trunk as the tree is tall.  This root growth can be quite rapid, with the roots growing to three times the branch spread within two to three years after planting.  Just imagine how far out the roots of large shade trees, with crowns that grow to heights of 50 to 80 feet, will reach!  The smaller the tree, the smaller the root problem.

Smaller trees seldom require extensive pruning to keep them in bounds.  Usually only minimal pruning ... to enhance the shape or remove limbs with undesired placement... is needed.  Large shade trees tend to outgrow their space in the landscape and can require costly, extensive pruning as they grow older.  Even large trees don’t “need” pruning except to remove dead or damaged wood.  However, pruning is frequently necessary to keep large trees within a reasonable size for the home landscape and to avoid problems with overhead utilities.

While there are a number of lovely shade trees available for use in the home landscape, few offer the seasonal interest that smaller specimen trees display... such as spring flowers, fruit and fall color.  Attractive bark and winter silhouettes are also desirable characteristics.

When selecting any type of tree you should consider:

1. Mature size of the tree: Is the tree suited to the site and home design?  A large shade tree must be sited where it will provide the shade needed and where its roots won’t cause problems.  The proximity to overhead and underground utilities, septic systems, swimming pools, building foundations, and paved areas should be assessed. In many situations you want to select trees that don’t grow too tall because they could block a desirable view from your home.
2. Pest resistance:  Small or large, it’s always a good idea to select a tree that’s not prone to insects or diseases.  This is important in reducing pesticide use and lowering the maintenance time required to keep a tree healthy.  Avoid pest-prone trees that will require lots of attention, such as white birch which is frequently attached by bronze birch borer or some varieties of flowering crab apples which are bothered by powdery mildew.
3. Adaptable to the climate and environment:  Many gardeners persist in planting trees not well suited to a particular area.  Trees should be winter hardy to UDSA Zone 6 and able to withstand the summer heat stress experienced in this region.  Trees that are marginally hardy or prefer milder summers, such as vine maple or quaking aspen, are harder to grow successfully here.  It’s upsetting to grow a tree for several years and then have it damaged or killed during a cold winter or stressed by hot summer weather.
4. Adaptable to site:  Pick a tree suited to the soil conditions and site that has been selected.  Trees that do better with in a protected location with some afternoon shade, such as flowering dogwood or Japanese maple, should not be placed on the south side of a building surrounded by concrete and rocks.
5. Trees with seasonal interest:  Many trees, especially the smaller trees, offer seasonal interest to the landscape... flowers in the spring or summer, fragrance, fall color, fruit, interesting bark, or distinctive winter form.  Don’t just settle for nice green leaves in the summer, select a tree that will provide you with appeal all through the growing season.

Small Trees to Consider for Our Region

Flowering Dogwood (mature height 15' to 25' depending on the cultivar) - this is a favorite small tree of many gardeners but it’s not really well adapted to our summer climate and often suffers summer leaf scorch from extended spells of 90+ degree weather. While it’s difficult to establish in this area, once it’s growing well it seems to thrive here.  It has wonderful white flowers in the spring and a rich red fall color with bright red berries. It should be planted in a protected location.

Japanese Maple (mature height 6' to 20', depending on the cultivar) - another favorite gem of gardeners everywhere, but it’s also generally not well adapted to our summer climate or soils and often suffers from leaf scorch when not placed in a protected site away from hot summer sun and wind.  In the right place this can be the most beautiful tree anywhere.  It may not have remarkable spring flowers, but its delicate dissected leaves and fall colors are a delight. There are upright and graceful weeping forms available. Some forms also have colorful winged seeds that provide color interest in the summer.  Be sure to look for heat tolerant cultivars.

Flowering Cherry (mature height 12' to 50', depending on cultivar) - perhaps one of the most beautiful small flowering trees available.  You’ll find a variety of flower forms from white to pink; large or small; single or double.  The tree form varies with upright, spreading, and weeping forms available. Many cultivars have a bronze to deep red fall color.  Borers can be a problem, especially if the tree is stressed, and is also subject to several fungus diseases that attack trunks, leaves and twigs.  Consider a flowering cherry a short-lived (20 years) tree.

Paperbark Maple (mature height 25') - this is an interesting little maple with dark green, tri-foliate leaves that turn a brilliant red in the fall.  The exquisite reddish bark peels off in thin sheets.  The form is upright oval to round.  This is a wonderful small maple, especially in the fall and winter landscape.

Redbud (mature height 20' - 25') - here’s a tree that everyone falls in love with when they see it in springtime bloom, especially those cultivars with deep, purple-rose flowers. Flowers come out before the leaves in early spring and adorn the bare branches. The tree usually branches close to the ground and develops a spreading, somewhat flat-topped crown.  Look for heat resistant varieties like `Oklahoma’ with glossy leaves and red tipped new growth.

Amur Maple (mature height 5' to 25' depending on the cultivar) is another small maple that should be considered for its magnificent orange-red fall color. This tree is a low branched, multi-stemmed tree with a variable shape. It’s very winter hardy and can be utilized in above-ground tree planters. For dependable fall color select a cultivated variety, such as `Flame’ or ‘Red Rhapsody.’

Dwarfs or Giants

In the nursery trade there are some cultivars of larger trees that meet the size criteria of a “small” tree. While they may not have quite the pizzazz of these other smaller flowering trees, they can still be utilized in the landscape where a smaller tree is needed.

Leprechaun™ Ash is a dwarf form with a mature height of 18' of the green ash.

Golden Desert Ash™  (mature height 20') is a cultivated variety of the common or European ash with yellow-green leaves and bright golden twigs. 

Red Cascade™  or Dwarfcrown is a compact (mature height 16', mature spread 8') cultivated variety of mountain ash with an oval shape. It has white spring flowers, yellow-orange fall foliage, and orange-red berries for multi-seasonal interest. `Longwood Sunset’ is another smaller mountain ash with orange berries

Globe Norway Maple (mature height 15') is a “lollipop” tree with a dense rounded head that is much shorter than other Norway maples.  This is a very formal looking tree.

Harder to Find and Not Well Tested for This Area . . . But Worth a Try

Serviceberry (mature height 15' to 20') might be called a shrubby, multi-stemmed tree or a large shrub with early spring white flowers and bright red fall color. Some cultivars also have purplish blue berries. Plant these in a more protected location where they’ll get afternoon shade.

Japanese Tree Lilac (mature height 20') is another shrubby tree or large shrub that develops a graceful form with age. It’s covered with showy white flowers in the spring, but their fragrance isn’t the lovely scent of the common lilac. It may not stand up well under our summer heat, so plant where it will receive afternoon shade.

Kousa Dogwood or Chinese Dogwood (mature height 20') is not as well known as its cousin, but Kousa cultivars deserve just as much attention for their striking flowers.  Here’s another one that should be kept out of the afternoon heat and you’ll need to condition the soil with organic matter, sulfur, and acidifying fertilizers since it prefers acid soil conditions.

Persian Parrotia (20' to 40' in the south) this is a beautiful tree with unusual upright or spreading oval form and texture. Its fall color is a breathtaking mix of yellow, orange and red. The bark is an interesting exfoliating gray, green, white and brown.

Austrees and Hybrid Poplars

Marianne C. Ophardt
Washington State University Extension
Area Horticulture Specialist  

They often sound too good to be true... advertisements for fantastic plants and super trees.

The Austree is actually a hybrid willow tree.  It's a cross between the Hankow willow (Salix matsudana) and white willow (Salix alba). Willow trees are fast growing trees and the Austree is no exception.  The advertisement indicates that they're "very fast growing" and can grow as much as fifteen feet a year.  I don't doubt this one bit, especially with our local summer sunshine and heat. The advantages to a fast growing tree are obvious, but fast growing trees tend to have soft wood that breaks easily and is prone to wood rot. 

Fast growing trees also tend to have large, invasive roots systems, and the Austree is again no exception.  The ultimate mature height of the tree is 50 to 70 feet and the literature suggests that the roots can extend into the soil two to three items the height of the tree.  Austrees are used to stabilize slopes and minimize soil erosion in gullies.  This implies a very invasive root system... it has to be to help hold onto the soil.

The literature also indicates that the Austree has problems with alkaline soils where the pH is above 6.5.  Most of our local landscape and garden soils are above 8.0 which means that the Austree may have problems here.  This can be ameliorated by fertilizing with an acidifying fertilizer, such as ammonium sulfate or sulfur coated urea, on a regular basis.  Failure to amend the soil could lead to poor growth and performance.

The Austree is also susceptible to the same pests and diseases as other willows growing in our area.  The two most common pests that I've seen on willow leaves are aphids and mites. These can be controlled with applications of pesticides, but it may be difficult spraying large trees.  

What it all comes down to is that Austree should not be considered as a shade tree for a regular- sized or small home lot.  They should work well here for stabilizing slopes, creating a dust and noise barrier, acting as a windbreak, acting as a wildfire break, or providing a privacy screen.  They should also be useful in creating shelterbelts and wildlife habitat. 

The important thing to remember is that they do have an extensive and invasive root system.  They should be located where this will not create a problem with driveways, sidewalks, septic systems, buildings or other structures. Another thing to know about making the Austree into a hedge or windbreak is that they should be planted about three feet apart in a single row planting and five feet apart in a double row planting.

The fact that these trees have lots of roots also implies that these trees like lots of water...  and that's true.  The Austree people recommend that after the seedlings are established they should have a good soaking every three days.  In fact, they recommend irrigating with drip irrigation to make this easier.

Planted in the right place for the right purpose, the Austree might have a place in our local landscape.  However, I'd recommend staying away from it as a shade tree for the home landscape.

Hybrid poplars are another tree being touted by many because they grow so fast.  Just look at the hybrid poplar plantations that are grown for pulp, fuel, lumber, and plywood.  It's truly amazing just how fast some of these hybrids grow!  Unfortunately, the hybrid poplars are not well suited as a shade tree for the home landscape.  The same reasons that make the Austree willow unacceptable also apply to the hybrid poplar... they have invasive roots and brittle wood.  Large limbs of brittle wood and potential wood rot lead to limb breakage and potentially hazardous situations.

However, the hybrid poplars do grow fast and are less susceptible to some diseases than Lombardy poplar, the variety traditionally used for windbreaks.  These new poplars are preferable over the Lombardy for windbreaks because of their rapid growth, their dense green foliage, and the absence of root sprouting.  The use of male clones can also avoid that nasty problem of blowing cotton.

The Rocky Mountain Austree Company offers two interesting hybrid poplars. One is called 'Rapid Merlot'  which leafs out in the spring with deep green and maroon leaves.  The leaves turn darker green during the summer and change to maroon again in the fall.  The Austree company notes that this is a good tree for windbreaks and can grow from 10 to 15 feet in one year.

`Gold Panner' is also a hybrid poplar offered by Austree Co.  This one only grows five to eight feet a year and is recommended for shade tree use instead of windbreaks.  Keep in mind that this is still a poplar tree and with typical poplar problems. Spring leaves are large and golden-yellow in color with purple stems and veins.  They tend to change to a lime green in mid-summer and then back to a brilliant gold in the fall.  I like my trees a dark green so I'd personally stay away from this tree, but the coloring does sound distinctively different. 

Until recent years local poplars and willows weren't bothered with many serious pests.  However, there is an increasing problem with borers on both poplars and willows in this area.  One borer is the "poplar and willow borer."  There is also the carpenter worm, which attacks both trees too.  These can structurally weaken limbs and can lead to the death of the trees.  Control involves keeping the trees in good health and applying a pesticide spray at the recommended times.

Another insect problem that's becoming widespread on poplars is the lettuce root aphid.  This aphid causes a reddish, flask shaped gall on the leaf stems.  It was first thought to be harmless, but apparently high populations of the pest are capable of causing damage and tree decline.  This insect can also be controlled with sprays... if one has the equipment to spray tall windbreak poplars.

In conclusion, Austree willows and hybrid poplars could have a place in the landscape, but we should realize that they're not problem-free and should be used where you can take advantage of their best characteristics and avoid problems from their poor traits.