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.

Tree Roots Cause Problems with Mowing

Tree Roots Cause Problems with Mowing

Marianne C. Ophardt
Washington State University Extension
Area Horticulture Specialist  

Roots of large shade trees such as silver maple, sycamore and others often create problems when mowing the lawn.  Does it hurt the tree to cut the big roots off?  Would it be better put some soil over the top of the roots to make the surface nice and smooth?

Neither of these is a good solution to the mowing problem.  Severing of large, major tree roots will significantly impair that tree's ability to absorb water and nutrients from the soil.  Removal of large roots also weakens the tree structurally.  Remember the large woody roots help to anchor the tree.

Raising the grade around the tree more than one or two inches can smother the fine feeder roots on a tree.  Roots can't live without oxygen and even several inches of soil can hurt the roots of certain trees.  Deeper soil piled around the trunk of the tree can lead to rot at the base of the trunk... leading to tree decline and death.

Unfortunately, there is no good or easy solution to your problem.  You might try killing the grass and mulching the area with bark mulch, being sure to keep the mulch several inches away from the tree trunk. 

What are Girdling Roots?

What are Girdling Roots?

Marianne C. Ophardt
Washington State University Extension
Area Horticulture Specialist  

There are many diagrams that show trees with a big tap root directly beneath the trunk. This concept has been proven wrong by many different research studies of tree roots. Most trees do not have tap roots, especially when the soil is compacted or where the there is a high water table. You will not find tap roots on most of the trees in your yard. The exception to the rule might be pines and oaks which as young trees may have tap roots in sandy, well-drained soils.

If there aren't deep tap roots in the soil, where are the roots? Most tree roots are in the top 6 to 24 inches of soil. Tree root systems consist of larger, woody perennial roots and smaller, fine feeder roots. The woody perennial roots grow mostly horizontally in a network that radiates outward from the base of the trunk. Most of these roots will be found in the top six inches of soil, but vertical anchoring roots along this horizontal network may grow several feet deep or more. The function of the woody perennial roots is anchorage, water conduction, mineral transport, and food storage.

The fine feeder roots are much smaller than the perennial roots. They grow outward and upward from the perennial roots and are predominantly located in the top several inches of soil. Feeder roots die and are replaced on a regular basis. Their function is water and nutrient absorption.

It’s not unusual to find young nursery trees with kinked, entwined or circling woody perennial roots.  Once planted in the landscape, these roots grow in girth and can "girdle" or strangle the tree, preventing water and nutrients uptake. Girdling or circling roots also compromise the structural integrity of a root system and can lead to wind-throw in severe winds.

Sometimes circling roots on established trees can be cut with a sharp knife or chisel, but often the problem is noticed too late for this corrective action. If you suspect that your trees have girdling or circling roots, consult an arborist before taking any action. Keep in mind that large woody roots are your main framework of the root system. Cutting large roots can further compromise their anchoring ability.

Avoid girdling root problems when purchasing trees. Check the root systems before planting and only accept trees with well-distributed root systems, ones without kinked or circling roots.

Avoiding Girdling Roots and Planting Problems

Avoiding Girdling Roots and Planting Problems

Marianne C. Ophardt
Washington State University Extension
Area Horticulture Specialist  

How long will my tree live?  If it's in a protected place on a college campus, it may live 40 to 80 years.  If it's located in a city park, with luck it will survive 25 to 30 years; and if it’s growing in a suburban street right-of-way, it might last 12 to 18 years.  In cities, trees last only about 3 to 4 years.  Why?  Experts indicate that it's usually not insects or disease that ravage these trees... it's most often related to problems with the tree roots or the soil.

The same holds true for the sick or unthrifty trees.  The problem is usually not an insect or disease, it's most often related to a problem with the roots...  improper planting techniques; girdling or encircling roots; poor soil conditions; and watering difficulties.  Many young trees die before they ever develop a good root system. 

Let's talk a little about roots. Roots are alive. They need oxygen for respiration and normal plant metabolism.  It's easy to forget the importance of roots to a tree.  They enable a tree to take up water and nutrients in the soil.  Roots store carbohydrates and synthesize organic compounds involved in regulating plant growth.  For a tree to be healthy, the roots must be healthy.  According to Dr. Rita L. Hummel, Washington State University Horticulturist, "The importance of healthy roots and a favorable root environment cannot be overstated."

If so many tree problems involve roots and problems with root systems, where do these problems originate?  Some are due to faulty root systems that developed in the nursery where the trees were first propagated.  It is there that roots develop kinks or sharp bends.  This is due to the handling of the seedling in the nursery.  With mass production and mechanization of the nursery industry, seedlings may be jammed into pots that don't have adequate room for their root system.  In other cases, the seedlings are left too long in smaller pots before they are planted into larger pots.  When planted into the larger pots, the roots continue to grow in a circle and never fill out into the larger root area.

"Once formed, kinks, circles, and girdles in woody root systems have three possible fates: 1) the root dies; 2) the kinked or circled portion of the roots is pruned out at transplanting; or 3) the root lives... and grows in circumference until at some point the root girdles itself, the stem, or another main root.  This can restrict the flow of water and nutrients in the plant and compromise the ability of the tree to support itself," says Hummel.  It may take many years for the root problem to become apparent, evidenced only by the gradual decline of a tree or a tree may fail to grow well from the time of planting.

To diagnose a tree problem as a "root or soil problem," the owner must check the root system. It's easy to check the leaves or trunk of a tree for a problem, but how do you check the roots? You can look for girdling roots by inspecting the tree where it enters the ground.  In some cases you'll be able to see roots that are twisted around the trunk and are girdling or "choking" the tree.  However, girdling roots can also be under the surface of the soil.  A clue that the girdling root is a problem will be a lack of the normal flare to the trunk on one side of the tree.

If you suspect that there are girdling roots below the soil, you'll need to carefully excavate around the trunk.  You can do this by gently removing the soil from around the tree base until you find the main roots.  A watering can or hose can be used to help clean the roots for your scrutiny.  If the main roots radiate out from the trunk unimpeded by other roots, girdling roots are not the problem.  Girdling or encircling roots restrict the growth of the trunk and roots.  If girdling roots are found, a trained arborist can help you decide what action to take.  In some cases the offending root can be cut, solving the problem.  In other cases, the problem may require removal of the entire tree for safety. 

Younger trees that fail to thrive and grow after a year or two, should be checked to see if the roots have grown out of the original root ball.  This should also be done very carefully, trying not to sever roots.  Check is the depth of planting.  The top of the root ball of a mulched tree should be just below the soil surface.  Anything deeper than an inch or two is too deep.  In this situation, the roots can't get air and will gradually die... and the tree will die too. 

When you dig down to check the root depth, don't look for the fine feeder roots proliferating at the top of the root ball and assume that everything's satisfactory.  In some cases, this is the only place where roots have grown, because it's the only place that they could get some air.  You should find the main woody roots radiating out from the trunk just below the soil surface.  Ifthese main roots are deeper, you should replant the tree at the proper depth.  Do this in early spring before new growth begins or in the fall after the leaves drop.

Another "root" problem that may also be revealed in a root ball excavation... is the failure to loosen and cut encircling roots of container grown trees at planting time.  Locally, we've seen trees and shrubs that have been in the ground for five years or more which seem to do fairly well and then gradually die.  Upon removal, their owners have found that the root ball kept circling in the same pattern of the original pot and the roots never moved out of the root ball.  In fact, the root system even fit back in the original pot several years or more after planting!

Yet another "root" problem that shows up when tree root balls are excavated... is the failure of trees roots to grow beyond the original root ball with balled and burlapped trees.  While landscape contractors' standards often specify leaving the bottom portion of burlap around a root ball, there are problems with this practice.  In many cases the burlap fails to rot and roots don't grow beyond the burlap, even three years after planting.  To avoid this problem, remove the burlap once the tree is situated in the planting hole at the correct depth. Cut the burlap away from the root ball, moving of the root ball as little as possible.

Finally the old adage of "hindsight is better than foresight" doesn't necessarily hold true when considering girdling tree roots and related root problems.  Most of these problems are better avoided in advance by checking trees for kinked and girdling roots before planting and then following proper planting procedures.  In this case, hindsight is just too late to save many of the trees.  Pay attention to the roots before you plant and help your trees live longer!  

Staking and Wrapping Trees at Planting Time

Staking and Wrapping Trees at Planting Time

Marianne C. Ophardt
Washington State University Extension
Area Horticulture Specialist  

Trees are an investment whether they’re part of a home, commercial, or public landscape.  It’s a shame to see them die needlessly because they were planted improperly or not given good care after planting.

Staking

While staking a tree at planting time is occasionally done in home landscapes, it is more common in commercial and public plantings that have staking included in the installation specifications.  In some cases staking is intended to protect young trees from vandalism and accidental physical injury... from car doors and fenders or errant shopping carts.   Staking is also often done to protect trees from falling over in the wind or to support trees that aren’t strong enough to stand up straight by themselves.

In the past, tree staking was believed to be important in helping a tree become established in a landscape.  However, in recent years research has shown that staking often hurts a tree more than it helps.  Here are problems with staking trees and their solutions:

Staked trees, especially those improperly staked, tend to develop smaller root systems and thinner trunks, as well as growing taller than trees that aren’t staked.  The movement of the tree trunk in the wind stimulates plant hormones that in turn stimulate root and trunk growth.  When a tree is staked in a manner that prevents any movement of the trunk, the tree doesn’t establish and grow as strong.  This is why young trees that are staked, are often unable to stand upright when the staking is removed.

SolutionDon’t stake a tree unless it’s needed.  Usually, trees less than six feet tall or trees less than one inch in diameter won’t need support staking.  Staking may be needed with larger trees, especially when the top of tree is out of proportion to the root ball or when the tree is planted in a windy site or on sandy soil. 

When a tree must be staked, use two sturdy stakes, such as 2x2 wood posts, placed outside the root ball.  They should be situated so that the trunk is allowed to move with the prevailing winds.  Stakes should be driven 18 inches or so into the ground.

Staking may also be needed when you buy a tree with a weak trunk that can’t stand upright without support.  Personally, I would avoid trees with these weak trunks and you should too.  Staking may also be needed in public areas to protect against physical injury or vandalism.

The old standard of wire or plastic twine inside pieces of garden hose can cause damage to the bark and trunk tissues.  These materials often cut into the bark and girdle the tree as it grows in girth, especially when not removed the first year or two after planting.  Just look around at some of the commercial landscapes in our area that were planted within the last five years.  You will no doubt find wire or other tying materials still securing the tree to the stakes, or at least still tied to the tree trunk.  They may already be restricting growth and transport of water and nutrients up and down the trunk.

Solution

Don’t ever use rope, twine, wire, fishing line, or electrical wire to secure a tree to stakes.  Use soft materials like wide cloth belting, elastic webbing, wide rubber belts, or even nylon stockings.  There are a number of elastic or polyethylene woven ties now available for securing trees to stakes.  Ties should be left with sufficient slack to enable the tree to move in the wind, but without rubbing against the stakes or moving the roots.

Whoever is responsible for the care of the staked tree... home owner, landscape manager, or business owner... should periodically inspect tree staking for signs of trouble.  They should also start removing the staking as soon as the tree is established... after the first year after planting.

Guy wires sometimes used for staking large trees can be a hazard, as well as a nuisance when mowing.

Solution

Use guy wires only on large trees with trunks that are greater than four inches in diameter.  Three to four wires are typically used to anchor a large tree.  Mark guy wires with bright flagging tape or streamers to let people know that they’re there.  Renew this flagging as long as the wires are present.

Sometimes you’ll see trees staked with a single stake.  In some cases, the trunk above the tie will grow larger than below the tie... again because of the movement of the trunk.  The tree may also bend away from the stake.

Solution

Stake trees using two supports.

Wrapping

For many years arborists and horticulturists have recommended protecting young tree trunks with commercially available trunk wraps.  These wraps were believed to protect the tree from physical injury, from frost cracking and sunscald that result from drastic fluctuations in temperature, and from drying out.  New research indicates that these tree wrap hurt trees rather than protects them.  Paper wraps appear to hold in moisture and lead to problems with disease fungi, insects, and freezing injury.  Severe temperature changes have also been found to occur beneath the wraps. 

There are a number of materials that have been used to wrap trunks.  Older and most familiar is a trunk wrap made out of kraft paper.  In more recent years there have been other commercially-produced guards, generally made from plastic.  Home gardeners have made some of their own wraps out of various materials such as burlap wrap or duct tape.  Many of these homemade wraps have been attached to trunks with string, twine, tape, plastic ties, or other materials that don’t degrade rapidly.  Like staking ties, these materials have also caused harm to trees by restricting growth or girdling trunks.

Solution

Because of this new research, it’s advisable to avoid the use kraft paper wraps with the black tar-like backing or most other tight fitting wraps.  If guards are used to protect against physical injury, they should fit loosely to allow for air circulation and to prevent the build-up of moisture or temperatures. 

If trees are protection is needed against sunscald on thin‑barked trees, such as ash, birch, linden or maple, a loose fitting tree guard in a light-reflective color would be better than a trunk wrap. 

As with tree staking, trunk guards should be inspected periodically to make sure they aren’t restricting the trunk.  Most guards can be removed six to twelve months after the tree is planted.  Always remove wraps that come with a new tree.  It was there to protect the bark during transport.

Keep your trees alive and protect your investment in them by checking them periodically for problems and by removing staking and guards when they aren’t needed anymore.

When Strong Winds Uproot Trees

When Strong Winds Uproot Trees

Marianne C. Ophardt
Washington State University Extension
Area Horticulture Specialist  

It’s not unusual in this region for strong winds to sometimes blow trees over and or at least cause them to lean a bit more than they had been before the windstorm. Why do trees fall over in the wind? It’s usually due to the failure of the root system to keep the tree upright, not the size of the tree.  In addition to absorbing water and nutrients, roots have the task of job of anchoring the tree along.

There are many diagrams of trees that show large trees with a big tap root directly beneath the trunk. This concept has been proven wrong by many different studies of tree root systems. Most trees do not have tap roots, especially in urban situations where the soil is compacted or where the there is a high water table.  You will not find tap roots on most of the trees in your yard. 

Most tree roots are in the top 6 to 24 inches of soil.  Tree root system consists of larger, woody perennial roots and smaller, fine feeder roots.  The woody perennial roots horizontally, radiating outward from the trunk.  Most of these roots will be found in the top six inches of soil, but vertical anchoring roots along this horizontal network may grow several feet deep or more.  The function of the woody perennial roots is anchorage, water conduction, mineral transport, and food storage. 

The fine feeder roots are much smaller than the perennial roots.  Their function is to absorb water and nutrients. They grow outward and upward from the perennial roots and are predominantly located in the top several inches of soil.  Feeder roots die and are replaced on a regular basis.  These feeder roots are only about 1/16 of an inch in diameter or smaller and increase the root system's surface area.  This is important because, the greater the surface area, the greater their capacity to provide water and nutrients to the tree.

Major perennial tree roots may not be as deep as we've imagined in the past but they are longer than most people think. The framework of roots often grows outward to a diameter one to two times the height of the tree.  This is much further than the simple branch spread or "drip‑line", where they were once thought to terminate.  On average, tree roots spread about three times the spread of the branches.  Studies have indicated that over 50 per cent of the roots are outside the drip‑line.

The major perennial roots have the job of anchoring the tree.  In order for a root system to support a large, long‑lived plant like a tree, it must be free of structural defects and the main structural roots should be distributed evenly around the trunk.  Wind‑throw results most often from poorly distributed roots or poorly developed root systems. 

Poorly distributed roots can result from kinks and circling roots; improper planting practices; physical damage or severing of roots; restriction of root growth; or death of roots from cultural or climatic factors.  Poorly developed root systems can result from improper planting practices; compacted and shallow soils; and poor growing conditions.

Roots fail to hold a tree upright when there isn't a healthy, well‑distributed root system.  When a tree uproots and falls over in the wind, we have to ask ourselves what caused its failure.  This takes examining the roots and trying to detect the cause.  It also involves reviewing the trees situation and history.  Were major tree roots severed recently or years ago?  Were there any girdling or kinked roots evident?  Was there a poorly developed system?  What might have been restricting root growth on one or more sides? 

Can fallen trees be uprighted and saved?  Large trees, over eight feet tall, can't and shouldn't be saved.  Removal is the only option.  Even if you can successfully upright the tree, it may become a hazard because of the damage that has occurred to woody roots anchoring the tree.  Uprighted trees can pose a serious hazard, especially as they grow in size and girth.

For trees smaller than eight feet, it may be possible to upright the tree and save it.  However, it will probably only be successful if one‑third to one‑half of the roots are still in the soil and not exposed and if the roots which are exposed are fairly compact and undisturbed. 

The process of “uprighting” the tree may require some type of lift equipment to pull the tree upright.  Before pulling it upright, you should remove some of the soil beneath the exposed root mass to allow the root mass to be situated at soil grade level.  Once you have the tree back in place, fill in the soil around the roots as needed, being sure to keep the tree at the same soil level as it had been growing.  Water the tree thoroughly to get rid of air pockets and settle the soil around the roots.

Since the tree has lost a portion of its anchoring roots when it blew over, you will need to provide some support in the form of staking.  Drive two stakes into firm ground about six to eight inches away from the trunk.  Then tie the trunk to the stake at the lowest height which stabilizes the tree in an acceptable upright position.  The stakes should be removed when the tree can stand by itself.  Check the tree every year to make sure it's still stable.  If it's not, removal may be needed to maintain safe conditions.

Scale Insects

Scale Insects

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

Scale insects are positively insidious. As female scale insects mature, they settle down to feed on a plant, hiding beneath a convex shell-like scale covering.  The female scales never move again.  Concealed beneath the armor-like scale, they often go unnoticed because they don’t move and they don’t look much like insects.

Damage

You might wonder what damage is caused to plants by these sneaky little creatures.  Scales feed by sucking sap from plants.  While a few scales won’t harm a plant, large numbers weaken it.  A heavy scale infestation can make a plant more prone to damage from drought or severe temperatures and make it more susceptible to attack from other insects.  Heavy scale infestations can also lead to the death of branches and limbs or possibly an entire plant.  Some species of scale inject a toxin into a plant as they feed, causing even greater damage. 

Certain types of scale suck out more plant sap than they can use.  They expel the excess sap as a mixture of liquid and sugar called “honeydew”.  The sticky honeydew is not harmful, but it can serve as a food source for the “sooty mold” fungus.  Sooty mold is a black fungus that lives on the secreted honeydew, coating leaves or needles and detracting from a plant’s appearance.

Life Cycle

If the adult females don’t move once they start feeding, one might wonder just how they spread from plant to plant.  Before we can answer that question, let’s take a look at the life cycle of scale insects. Most scale insects start their life as eggs.  These eggs hatch and become immature scales, also known as nymphs.  These immature scales are mobile and referred to as “crawlers”.  The crawlers have six legs and walk around looking for a place to feed on the new plant growth. 

When they are ready to settle down and feed, the crawlers molt and begin forming the scale over their bodies.  They produce this scale covering from waxy filaments and feces.  The shape, color, and size of the scale are distinctive for each species of scale.  The scale covering provides protection from being eaten by other insects... and also from being killed by insecticide sprays.

Once the female scales have settled down to feed and secreted the scale covering over their backs, most species lose the use of their legs.  Male scales are different.  They develop under thin scales and emerge as winged forms.  Their only purpose in life is to mate.  They have no functional mouthparts and can’t feed.  After they mate, the males disappear.  The females then produce eggs (some species produce live nymphs) under their scale covering or in some type of cottony material... and thus the cycle of lives begins again.  Most species of scale that attack outdoor trees and shrubs in our region have only one generation a year.  However, scale insects found on indoor and greenhouse plants can produce several generations a year. 

It is in the crawler stage that scales move from plant to plant, but the tiny crawlers can’t fly and aren’t able to crawl or walk to different plants.  They are moved about in different ways. Their mode of transportation can be the wind, other insects, birds, animals, or even man.

Managing a Scale Infestations

Managing a scale infestation is not an easy task.  Because of their sneaky nature, scale populations tend to build up to large numbers before they’re noticed.  It’s also especially difficult to control these insects because their scale protects them from most insecticides.  Some scales can be controlled with dormant oils applied in late winter.  The oils work by suffocation.  However, it’s in the unprotected crawler stage that scales are most vulnerable to control with insecticide applications.  The problem is that the crawlers are so small it’s difficult to detect their presence and there is a relatively short time before they start covering themselves with a scale. 

A magnifying glass or hand lens will assist you in seeing them.  You can also trap crawlers with double-sided sticky tape wrapped around twigs and branches.  About the time when the crawlers are expected to emerge, place the tape near adult scales and trap the crawlers as they move out to feed on new growth. You may need to renew the tape from time to time, when it loses its stickiness.  Keep an eye on the tape and apply the appropriate sprays when they emerge. 

Scale Insects Troublesome to Trees & Shrubs in Our Region

Pine Needle Scale: This scale is a often problem on stressed pines, especially older trees or those located in dusty areas.  Pine needle scale is white, pear-shaped and about 1/8 inch long.  Its feeding weakens and slows growth.  Pine needle scale can be controlled with dormant oil applied in the spring before new growth begins and with sprays at the crawler stage about April.

Spruce Bud Scale: More and more of this sneaky scale is showing up in local spruces.  It’s often found on the lower branches of spruce trees, but it’s not easily noticed because the scales resemble spruce buds and are located at the base of new twig growth.  Gardeners sometime notice the excessive amounts of honeydew produced by this scale; the bees and wasps attracted to this copious sweet residue; or the sooty mold growing on the honeydew.  However, it may not be noticed until dieback starts occurring.  Spruce bud scale can be controlled with delayed dormant oil in the spring and with sprays when the crawlers appear about June. (Be aware that oil sprays will turn a “blue” spruce to green.)

Juniper Scale: Here’s a little round scale that feeds on the needles of juniper, arborvitae, chamaecyparis, cypress, and red cedar, but it’s most often seen on juniper in this region.  The scale is off-white with a central yellow dot. It tends to be a problem on older, less vigorous junipers.  It can be controlled with dormant oil in late March to early April before new growth begins and with sprays when the crawlers appear about June.

San Jose Scale: This is also a very small scale (1/16 inch in diameter) round scale.  It attacks a wide variety of hosts including apple, cherry, pear, poplar, willow, maple, birch, and many other deciduous trees and shrubs.  It’s black and tends to blend in with the bark of many trees and shrubs. 

This is a common problem on fruit trees and is moved about by the wind, birds, and humans.  Predators sometimes keep small populations of San Jose scale under control, but rampant infestations can be quite damaging.  Control can be achieved with late winter dormant oil and with sprays when the crawlers appear in June and again in September.

Other types of scale sometimes found in this region include cottony maple scale on maples, oystershell scale on various deciduous trees and shrubs, elm scale on elm, and hemlock scale on spruce.

If you should notice some scale on one of your trees and shrubs, don’t panic. Many scale infestations are kept under control by natural enemies.  Sprays may not be warranted if predators or parasites have kept the population in check.  There are also cultural controls that gardeners can employ to assist with prevention and management.  First and foremost, keep your plants happy and healthy.  A tree or shrub that’s growing vigorously and not stressed will be less prone to attack.

Trees With Yellow Leaves That Should be Green

Trees With Yellow Leaves That Should be Green

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

The leaves of most trees should be green, but sometimes in the Mid-Columbia region, tree leaves turn from green to yellow.  It’s a problem called chlorosis.  Chlorosis is an abiotic (not caused by a living organism such as a fungus or virus) disease.  It’s characterized by the greenish-yellow to yellow leaves.

Much of the chlorosis seen in our area on trees is actually iron chlorosis or chlorosis caused by a lack of iron in the plant tissues.  Iron is needed for the formation of chlorophyll, the green pigment in leaves.  Without the green pigment that allows a plant to utilize sunlight for production of food and energy, the plant will die. 

Plants with iron chlorosis first turn yellow-green to yellow between the veins, with the veins remaining a darker green.  With more severe chorosis the leaves become pale yellow and develop brown spots between the main veins.  Leaf margins may also turn brown with the leaves later drying up and falling off.  Tree growth slows to a stop and dieback of branches can occur when iron chlorosis is extremely severe.

Iron chlorosis is quite common in our area because we tend to have alkaline soil, those are soils with a high pH, often over 8.0.  While our soils actually contain adequate amounts of mineral iron, its in a chemical form unavailable to the plants due to the high pH of the soil.  The yellowing or chlorosis can involve the entire tree, or may be restricted to one side or even just one branch.  Within the same yard, there may also be perfectly healthy green trees growing right next to ones with iron chlorosis.

Certain types of trees and shrubs are more prone to iron chlorosis than others because they are more sensitive to high pH soils.  Those trees most likely to show symptoms of iron chlorosis include Pin Oak, Flowering Dogwood, Sweet Gum, Silver Maple, Tulip Tree, Magnolia, Catalpa, White Oak, Holly, and White Pine.  Acid-loving shrubs, like azalea, blueberry and rhododendron, are also prone to iron chlorosis.  These types of trees and shrubs should be avoided when planting in soils where pH is extremely high.

While it’s common to encounter highly alkaline, calcareous soils in our region, a high pH is not the only cause of iron chlorosis.  First of all, it may not even be iron chlorosis.  Chlorosis can be confused with similar symptoms expressed by mineral deficiencies such as magnesium, manganese or boron.

Cultural factors can also lead to symptoms of chlorosis.  Overwatering is probably the most common cause of chlorosis, in fact iron chlorosis can be induced if soils are kept excessively wet as a result of overwatering, compacted soils, or poor drainage.  I frequently see tree and shrubs that have developed “lime-induced chlorosis” as a result of overwatering. 

Chlorosis can also be the result of root damage, girdling roots, or trunk damage from mowers and weed eaters.  This is because root restriction, root injury and trunk injury all impair the plant’s ability to take up and transport soil nutrients.  Chlorosis can also develop in extremely dry soil situations because mineral nutrients must be in solution for a tree to be able to absorb them from the soil.  In dry soils they can’t absorb the nutrients.  I commonly see chlorosis on many silver maple trees in situations where half of the root zone or more is located in an area that isn’t irrigated regularly, such as a dry lot, a gravel driveway, or a ditch bank area.

What can you do about chlorosis?  If the cause is excessively wet soils, adjust the watering so the soil doesn’t remain saturated for any length of time.  You will still need to water the tree adequately so it doesn’t undergo drought stress.  Watering should be done slowly enough to moisten the soil to a depth of at least 18 to 24 inches without saturating the soil.  If the soil is compacted, aeration may help the water penetrate the soil more quickly.  If the soil is too dry, the remedy is simple... water regularly to maintain moist soil to a depth of 18 to 24 inches in the entire root zone of the tree.

If watering or compacted soils doesn’t seem to be the problem, check for trunk or root problems.  Look for trunk injury from physical wounds to the base of the tree from mowers or weedeaters.  See if the bark on the southwest side of the tree has been damaged from winter injury.  Check for girdling roots, constricted roots, or damage to the root system.  When possible, these problems should be corrected.  In some cases the tissue damage may not be able to be corrected and the tree may eventually succumb to its injuries.

Finally, correcting iron chlorosis in alkaline soils isn’t an easy task.  Before you do anything, it’s a good idea to have a soil test performed to find out the alkalinity of your soil.  Once you have determined that your soil truly is alkaline, there are several approaches you can take to attempt to correct iron chlorosis.

One of the simplest approaches is to acidify the soil.  This is most easily achieved by adding sulfur to the soil prior to planting, but acidification is a slow process and pH change will be slow.  To acidify the soil you should add sulfur to the soil, prior to planting.  The easiest sulfur to use is prilled sulfur.  This should be applied at the rate of 25 pounds per 1000 square feet of landscape bed and mixed well with the soil to a depth of 18 to 24 inches.  If trees and shrubs are already established you will need to apply acidifying fertilizers, such as ammonium sulfate.

Another method of correcting iron chlorosis is the application of iron chelates to the soil.  Chelated iron is less affected by soil pH and more readily available to plant.  Iron chelates must be placed in the root zone by drilling holes in the soil or working it into the soil. 

Iron chelates in soluble form or iron sulfate can also be applied to plants through a spray to the leaves.  These foliar sprays often result in a quick “greening” of the leaves, but these effects are generally temporary.  New growth that develops after application will still be chlorotic.

There are also methods available for injecting iron right into trunk tissues with implants or injections, but these cause wounds to the tree trunk it’s not advisable to use them in most situations.

So if your trees are turning yellow, determine the cause and take action.  Keep you thumb and your trees green. 

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). 

The Use of Imidacloprid for Aphid Control in Trees

The Use of Imidacloprid for Aphid Control in Trees

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

Late winter is a good time to apply imidacloprid to shade trees for control of aphids in the coming season.  Imidacloprid, know commercially as Merit, is available to home gardeners under the name of ABayer Advanced Garden Tree & Shrub Insect Control Concentrate@.  It=s a liquid material that you mix with water in a watering can or bucket and then apply it to the soil at the base of the tree trunk.  It=s taken up by the tree and transported to the leaf tissues where it controls a variety of sucking insects, especially aphids. The amount applied is based on the circumference of the trunk at chest height. 

It takes a while for the chemical to reach the tops of tall trees... so late winter is a great time to apply the imidacloprid so it will be available when the leaves bud out and the early aphids start feeding.  The product is quite expensive and you may have sticker shock after you determine the amount you=ll need for larger trees, but it provides 12 months of control.  It=s also more environmentally sound, eliminating the difficulty of spraying the tops tall trees and removing the possibility of spray drift.  Beneficial insects are also protected by this method of application. 

Imidacloprid is also a good material for season long aphid control in roses.  However, the ABayer Advanced Garden 2 in 1 Systemic Rose and Flower Care@ contains fertilizer and a different systemic, disulfoton, that will only be effective for six weeks or less. It=s applied as a granular to the soil.  For season long aphid control on roses, use imidacloprid applied to the soil.  Just keep in mind that

Common Root Problems

Common Root Problems

Marianne C. Ophardt
Washington State University Extension
Area Horticulture Specialist  

Root problems are the number one cause of tree and shrub death in the home landscape. When the general care of a tree or shrub is adequate, root problems are suspected when a plant is growing poorly or showing signs of dieback.  Other symptoms of root problems include chlorosis (yellowing of the leaves) and leaf scorch (brown tips and edges of the leaf). Here are some of the most common root problems that lead to plant death in our local landscapes.   

PLANTING TOO DEEP:  Tomatoes don't mind a deep planting, but most trees and shrubs suffer from being planted too deep.  Plant roots suffocate and die when planted too deep because the roots can’t get the oxygen they need. Trees and shrubs should be planted at the same level as they were in the nursery or just slightly higher to allow for some settling of the soil.  This means that the top of the root ball should be at or just below the soil surface.

If you have trees or shrubs planted in the last five years that haven't grown very well and have exhibited chlorosis, leaf scorch, or die‑back of the twigs, check to see if the roots are too deep.  It's easy to check.  Just take a garden trowel and start digging down at the base of the trunk.  Just under the top of the soil you should be able to find the main roots radiating out from the trunk.  If you must dig down more than two to three inches to find the main roots, you and your plant have a problem.  While troublesome, replanting at the right level is probably the only real solution.

IMPROPER PLANTING: Improper planting should be suspected if the plant looks OK but doesn't grow much after several years from the time of planting or when the plant begins to decline after several years, often with symptoms of leaf scorch and chlorosis. 

When planting a tree or shrub that’s been grown in a container, encircling roots should be gently spread before planting.  Dense masses of fine fibrous roots need to be cut and teased out of the root mass.  Paper pots and burlap should be torn away or removed from the root ball once the plant is situated at the right level in the hole and positioned correctly.  This is especially important if the burlap is green or has a green tint to it.  This burlap has been treated with a copper solution to keep it from rotting in the nursery.  Copper is toxic to roots, so roots will not grow through this copper "barrier" even after the burlap begins to rot.

You can check for root growth by digging down at the edge of the original root ball.  Look for any root growth that has occurred since planting.  If plant roots weren't loosened or spread, it's likely that roots have not grown out from the original root mass. 

This problem occurs most frequently with plants grown in plastic pots, especially when the plants are simply "popped" out of the pots and plunked into a hole without any loosening of the root ball.  If someone else planted your landscape for you, you may want to check the situation of the roots before problems become apparent.  Replanting is the only recourse in this situation too.

WATERING: Because many container grown plants are grown in a "soilless potting mix" which is a coarse mixture high in peat moss or other organic matter, water does not move easily from the surrounding soil into the root ball.  You may have to water the individual root ball directly and not rely on sprinkler irrigation to provide adequate water.

It's especially important to keep the root ball of recently transplanted trees and shrubs moist for the first several months after planting.  Their roots are confined to a limited space, so they're unable to “reach” for moisture further outward or downward in the soil.  With our typical local summer climate, it's essential to pay close attention to watering the first summer after planting.  However, it's also important not to drown plants with too much water.  Don't allow water to puddle around the trunk or keep the roots saturated for any length of time. 

How can you tell if the soil is moist, too dry, or too wet?  Use a trowel, shovel, or soil tube to check for moisture in the root ball.  A dry soil will crumble when you try to make a ball of it in your hands; a moist soil will form a ball; and a wet soil will be muddy with excess water that can be squeezed out.

ROOT DAMAGE: Root damage can occur from any number of situations.  The most common cause of physical damage is from construction, such as trenching for utilities, driveway installation, or digging of septic systems.  Roots are often cut to accommodate the construction without the consideration of the damage caused to the tree.  Cutting off major roots, severs the main "pipelines" for the tree.  The tree can no longer access water and nutrients through the severed roots.

Root damage can also occur from a change of grade.  Most of the water and nutrient absorbing fine roots are in the top one-foot of soil.  Changes of grade in excess of four inches can severely reduce the amount of oxygen and water reaching these roots, eventually killing them.  In some cases, soil compaction and not extra soil from a change in grade can lead to the decline and eventual death of a tree.  Soil compaction also restricts oxygen and water uptake by the roots, leading to root decline and death.  Severe soil compaction is associated with roads, driveways, and the use of heavy machinery.  Moderate compaction can develop over time simply from human and animal foot traffic or from impact sprinkler irrigation.  This type of compaction can be partially alleviated with the use of a mechanical aerator.

Control Options for Trees with Sycamore Blight

Control Options for Trees with Sycamore Blight

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

Living in Prosser and working in the Tri-Cities, I have often been able to notice a distinct difference in the climates of each area.  This spring the disparity between the two has become very evident because of a disease problem showing up on sycamore trees. The sycamores in the Prosser and Grandview area have been hit hard by sycamore anthracnose, also known as sycamore blight.  It=s a fungus disease that attacks sycamore buds, shoots, twigs, and leaves. 

Our native sycamores, the western sycamore (Plantanus racemosa) and the American plane tree (Plantanus occidentalis), are very susceptible to sycamore anthracnose, a fungus disease common in this region.  The Oriental plane tree (Plantanus orientalis) and the original (not seedling offspring) London plane tree (Plantanus acerifolia) are more resistant, but not immune.  Resistant cloned cultivars include >Bloodgood=, >Columbia=, and >Liberty=.

This fungus attacks new tissues when they begin to emerge in the spring.  Infection is most severe when the weather is wet and cool with temperatures below 55 degrees.  Depending on the timing of the infection, the fungus may infect and kill expanding bud, shoot, and leaf tissues before they fully develop or it can attack leaves later after they=ve expanded.  On leaves, the fungus creates brown lesions that form along the midrib and main veins of the leaf. 

Cultural Control

Cultural control of the disease consists of raking and destroying fallen leaves and twigs along with keeping the tree adequately watered and fertilized.  On smaller trees it=s recommended to prune out and destroy infected twigs and branches.  Cankers on these infected branches provide spores for future anthracnose infections.  However, removal of cankers by pruning is impractical on large, older trees.

Fungicide Applications

Fungicides to prevent infection can be applied, but these are sprayed onto the tree when the buds begin to swell and the bud caps first start to break.  They are applied again 10 days after the first spray. Timing and good coverage over the entire tree is critical in getting control... something that=s very difficult with big trees.  

Injections for Control

One other control option is available.  This is an injection of a systemic fungicide into the tree.  This is done by drilling small holes into the trunk or root collar of a tree and injecting the material into the tree.  The fungicide is carried through the water-conducting vessels in the wood to the branches and leaves where it will protect against early season infection.  

To be effective this is usually done for two consecutive years.  Some materials are injected in the fall; other materials require an early spring application.  This procedure should be done only by a professional arborist trained in proper injection techniques.  Repeated use of this method may lead to eventual significant damage and wood rot because of the holes that are drilled into the trunk.

Careful Use of Weed Control Chemicals in the Lawn Protects Trees

Careful Use of Weed Control Chemicals in the Lawn Protects Trees

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

"Weed and Feed" or plain "weed" fighting chemicals can cause serious problems for trees and shrubs.  These materials are generally considered safe to humans, pets, and wildlife, if label directions are closely followed.  However, many weed control chemicals are not as safe to the desirable trees, shrubs, and ornamentals growing in the lawn or in surrounding planting beds.  The problem is not really with the weed killing products, but with us... those applying the products.  We frequently fail to read and fully understand the precautions given on the label.

Many products, especially those containing the active ingredient dicamba, advise against use in the root zone of desirable trees, shrubs, and other ornamental plants.  Damage often occurs when gardeners don't realize just where the root zones of these plants are located. 

Trees and shrubs are not tap-rooted (with a few exceptions). Roots expand laterally out from the trunk where there are larger "pipeline" roots that divide and subdivide, becoming smaller with each division until the very ends where the fine-feeder roots are located. The fine-feeder roots are responsible for absorbing water and nutrients from the soil.  The roots of most trees are found in the top 18 inches of soil, with over 50 per cent of their roots found in the top six inches of soil.  They're situated in this top layer of soil because that's where they can get the air, nutrients, and water they need for growth and survival.

Roots go out much further from the tree trunk than once believed.  It was once thought that most of the fine-feeder roots were located primarily in the drip-line zone. This is the area beneath the reach of a tree's side branches... the place where rain "drips" off a tree.  However, research has revealed that the root systems, especially the fine feeder roots, extend out laterally much further from the trunk.  In fact, tree roots often extend out from the tree trunk as far as the tree is tall... or even further.

Before we apply "weed and feed" or other weed controlling products to our lawns, we should step back and assess where tree, shrub, and ornamental plant roots may extend.  In most cases, it would be best to apply the chemicals only to the patches of lawn with weeds, not to the entire lawn where roots of desirable plants may be located.  If you have a large lawn with lots of trees and shrubs, these spot applications may be annoying, but they're important in protecting your plants from damage.

Of course if you don't have many weeds, it's much healthier for your trees and shrubs to either dig out the weeds by hand or spot treat individual weeds.  It's overkill to repeatedly apply herbicides to your entire lawn when you don't have many weeds.  The very best form of weed control is a healthy, dense lawn.  Proper watering, fertilizing, and mowing go a long way in helping you avoid the use of weed control chemicals... and protecting your trees, shrubs and gardens. 

If you chose to use weed control chemicals on your lawn. here are more precautions you should follow to protect your trees and shrubs:

Calibrate—  If you're applying a "weed and feed" or other weed controlling products, be sure to only apply the right amount. If it's a granular product and you're applying it with a drop spreader, be sure to calibrate your spreader correctly and only apply the amount needed for the square footage of lawn.  If you're applying the material as a liquid spray, you should also check the calibration of your sprayer or applicator.  Damage to desirable plants in the lawn or nearby plants is often due to over-application.

Do Your Math—  Do you know the square area of lawn that you're planning to treat?  Don't guess. Actually measure your lawn area and determine the square footage being treated. If your lawn is not an easy rectangle or square, determine the footage by breaking the area into rectangular, square, triangular, and circular blocks.

When Using a Granular—  Many of the granular materials will direct you to apply them when there is dew on the grass or when the grass is wet from a recent rain or irrigation. This helps the material stick to the grass and work more effectively.  If applied to dry grass, they will be much less effective.  There will also be directions on how long to refrain from watering and mowing, whether the material is applied as a spray or a granular.

Sensitive Plants—  Some plants are particularly sensitive to the application of dicamba and phenoxy (2,4 D, MCPP, and MCPA) herbicides in their roots zone.  Damage may occur even when you closely observe all the label precautions.  Trees and shrubs that are particularly sensitive to damage from either dicamba or phenoxy herbicides or both include apple, birch, box elder, catalpa, dogwood, forsythia, grape, honey locust, Norway maple, redbud, Siberian elm, sycamore, and walnut.  Extreme caution should be employed if you have any of these plants in your yard and you use these weed killing chemicals in your lawns. 

Avoid Drift—  Many broadleaf weed controls are applied to lawns as liquid sprays.  Extreme caution must be utilized to prevent drift to nearby areas.  Don't spray when it's windy.  The lower to the ground the application and the larger the spray droplets, the less likely drift will be a problem.  It's worth repeating...don't spray when it's windy or breezy.

What Weed Is It?  —  Get your weed identified first, BEFORE applying any chemicals for control.  If grassy weeds are the problem in you lawn, the typical "weed and feed" products for controlling broadleaf weed chemicals will not touch them.  If they're perennial grassy weeds, they will have to be spot- treated with a non-selective herbicide, such as Roundup or other glyphosate containing product.

If they're annual grasses, you will need to apply a preemergent herbicide, such as we discussed in a recent column. Effective herbicide applications for both perennial and annual weeds in the lawn depend on the type of grass and the appropriate timing of the application.  Get your weeds positively identified before attempting control.

Picking An Herbicide—  Not every weed is controlled by every herbicide chemical.  Most broadleaf weed control products for home gardeners contain more than one active ingredient.  2,4 D has been a popular ingredient for many years and provides good control of a number of common broadleaf weeds, such as dandelions and plantain.  However, there are other weeds for which it really doesn't do a good job of control.  Mixes of 2,4 D andMCPP or MCPA, are typically utilized.  These broaden the number of common broadleaf weeds the material will control, including chickweed, ground ivy, black medic, and clover. 

Many mixes now also contain dicamba to get at some of the more difficult-to-control weeds, such as bindweed, prostrate spurge, mallow, and oxalis.   Mixes that contain dicamba, 2,4 D, and MCPP are often referred to as "Trimec" when listed on the active ingredients of the label.

There are even tougher weeds, that the Trimec combination sometimes won't control.. A newer material, triclopyr, is now available to home gardeners to use on their lawns for control of some of the toughest lawn weeds, such as oxalis, violets, and spurge.  The only home garden product for use on lawns in Washington that contains triclopyr is Monterey Spurge Power that also contains dicamba and MCPA

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.

Fertilizing

Fertilizing

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

Poor fertilization practices can lead to problems with nitrates finding their way into surface water... streams, lakes, rivers... and into ground water. According to Mary Robson, WSU Area Extension Agent in the greater Seattle area, it’s important to apply fertilizers correctly to both provide needed nutrients to plants and to prevent runoff and leaching.

Robson directs her comments, not to the agricultural producer, but to home gardeners. She points out that at this time of year, many gardeners start thinking about applying fertilizer to their landscape and garden plants. Gardeners should apply fertilizers right before the plant buds break and start to grow. This time for our area would usually be in March and early April.

Trees, shrubs, and perennials plants utilize stored nutrient reserves during the first flush of spring growth. Fertilizer is applied to replace nutrients needed by plants and keep the plants healthy. Keep in mind that fertilizer is not plant “food.” Fertilizer simply provides the nutrients that a plant needs so that it can make its own food using energy from the sun by the process of photosynthesis

The following are tips that Robson offers gardeners regarding environmentally friendly fertilization of landscape and garden plants:

ESTABLISHED TREES & SHRUBS   Not all trees and shrubs will need fertilization. Large established plants will often get along fine with only a spring compost mulch or another organic mulch and no other supplemental fertilizer. What are the signs that a plant is growing well? If the plant develops good leaf color, puts on an average amount of new shoot growth and length per season, and generally appears healthy, fertilizer is probably not be needed.

YOUNG TREES & SHRUBS   A young landscape plant does need spring fertilization. If the garden has newly planted trees and shrubs, installed within the last two to four years, be sure to fertilize these to ensure the best growth possible.  Roots that are just getting established need extra nutrients in their second year.

WHEN TO FERTILIZE   It’s easy to over-fertilize, applying too many nutrients too often by assuming that landscape plants need lots of “plant food.”  Be sure to follow label directions for quantity and don’t add fertilizer to tree and shrub plantings after active spring growth has finished.  This means eliminating fertilizer applications to landscape plants after the middle of summer.  If you apply fertilizer too late in the season, the plant may fail to go into normal fall and winter dormancy and can be harmed by winter freezes.

NEWLY PLANTED TREES & SHRUBS   Robson recommends mulching newly planted trees and shrubs with two to three inches of mulch and then waiting to fertilize six months before applying any fertilizer to the newly installed plant.  This is good advice for the Seattle area.  However, many of our local soils contain so little nitrogen, that fertilization at planting time will greatly benefit plant growth.  Moderate amounts of slow-release fertilizer or tablets added to the planting hole can provide the needed nutrients as soon as the roots start to grow out of the original root ball.  If planting in a landscape or perennial bed, slow-release fertilizer and organic matter should usually be added to the soil when preparing the bed prior to planting.

Fertilizer bags often have confusing labels with different numbers.  Nitrogen is the main nutrient needed for good spring growth of woody plants.  Nitrogen is represented by the first number in the set of numbers on the fertilizer label.  Since that’s the primary nutrient needed by your trees and shrubs, you should look for a fertilizer where that number is larger than the other two numbers that represent the amounts of phosphorus and potassium.  Slow-release formulas are more expensive, but they’re best for your plants because nutrients are released gradually rather than all at one time.  Slow-release fertilizers generally lead to less waste and leaching of nitrogen and promote better plant growth.

If your trees and shrubs are situated in or next to the lawn area, they’re probably getting more than enough fertilizer through your regular lawn fertilization, especially if you aren’t using a slow-release material.  This can explain why you don’t usually need to fertilize these plants!  Yet, it’s important to note that the best times of year to fertilize lawns are not always the best time to fertilize trees and shrubs.  Washington State University Cooperative Extension recommends fertilizing lawns in September, early November, June, and May.

This dichotomy in fertilization times causes us a dilemma.  Should we fertilize the lawn at the right time or fertilize our trees and shrubs at the right time?  Fall fertilization can lead to problems especially when tender plants are fertilized late in the season.  Fall is the best time to fertilize our lawns to keep them healthy and thick enough to keep weeds out.  What should we do?  There may be no good solution.  However, try to avoid applying fall lawn fertilizers to areas above tender trees and shrub roots.  Slow-release fertilizers would help avoid a late flush of growth on woody plants that might be stimulated with a quick-release type of fertilizer.

How much fertilizer should be applied to individual trees and shrubs?  That’s one of those questions that’s hard to answer directly.  The amount of fertilizer needed depends on the size of the plant and the type of fertilizer applied.  To help you determine the amount of fertilizer you should apply to trees and shrubs, Washington State Unversity Cooperative Extension has a handy bulletin, “Fertilizing Landscape Trees and Shrubs EB1034," with the recommended rates and methods of application.  You can purchase one at your local county extension office.

How can you tell if your plants need fertilizer?  Look for plants that aren’t putting on good growth, where leaves are undersized and chlorotic or yellow.  Here again we have another dilemma, because these are also symptoms of other plant problems.  In many cases the symptoms of poor growth and yellow leaves turn out to be a root or soil moisture problem.  If the tree or shrub has trunk injury, root damage, girdling roots, root rot or excessive soil moisture or drought, the symptoms will be pretty much the same.  Fertilizer will not help these plants or solve the problem of poor growth.

How can you tell if this is a root problem or a lack of nutrients?  If most plants in the yard and garden are growing well without any special fertilizer applications, this is a hint that the affected plant has a problem unrelated to soil fertility.  If the problem happened over a fairly short period of time, this is a hint that a root or soil moisture problem is involved.  If you suspect a root problem, you can check it out by examining the base and roots of the plant.  This involves a process of gentle excavation.  Soil moisture in the root zone and irrigation practices should also be reviewed.

Robson wants home gardeners to know that fertilizing landscape plants isn’t just a matter of buying a bag of fertilizer and applying it.  Responsible, caring gardeners should observe the health and stage of growth of the plant first.  “Apply the right amount at the right time!”

When Staking is Left On Too Long

When Staking is Left On Too Long

Marianne C. Ophardt
Washington State University Extension
Area Horticulture Specialist  

Staking wire cans girdle a tree and lead to its death.  As a tree grows in girth, encircling wires “girdle” or choke the plant so that water and nutrients can’t move up and down the trunk.  Tree staking should be removed from trees as soon as possible after the tree becomes established.  It should never be left on the tree for more than a year. 

There are some cases where the tree grows over the wire and “grafts” to itself.  In those cases the tree survives but there is a permanently weak place in the trunk that is prone to breakage.  In cases where the wire isn’t completely enclosed in tissue and you can remove the wire without significantly harming the surrounding tissue, give it a try.

Keep this in mind too when there are plant tags, twine, or wire located on branches or trunks.  These materials don’t look harmful when the plant is young, but as the plant grows they can cause damage.  Even biodegradable strings and twines may not deteriorate before they girdle the plant.  Remove all “tying” materials when the tree or shrub is planted.  Don’t forget to remove staking as soon as the tree is established.

Take a look at recently installed commercial landscapes, those planted within the last two to three years.  In some locations, you're likely to see a number of trees where the staking has been left on much longer than needed and the wire is already cutting into tree trunks.

Planting Trees Correctly to Ensure Their Success

Planting Trees Correctly to Ensure Their Success

Marianne C. Ophardt
Washington State University Extension
Area Horticulture Specialist

Planting a tree isn’t as simple as digging a hole and sticking it in.  Many trees fail to grow and thrive because they aren’t planted correctly.  To determine just what is the “right” way to plant a tree, let’s look at some of the most common mistakes made when planting a tree or a shrub.

Too Deep

Probably one of the most common reasons for failure in planting trees and shrubs is that the root system is planted too deeply.  Roots need air.  They should always be planted at the same level or slightly above the level that they were growing in the nursery or in their container.  Planting them deeper than this deprives the roots of air and will eventually kill most plants.  Death is not usually a sudden thing.  Trees planted too deep will fail to grow well.  Leaves and new growth will be undersized.  Leaves may develop leaf scorch along the edges or become yellow and drop off the tree.  Keep in mind that trees aren’t tomatoes, most won’t tolerate deep planting.

Planting With Material Around the Root Systems

Any material around the roots... plastic twine, burlap, boxes, paper pots, and plastic pots should be removed at planting time.  Most gardeners don’t have to be told to do this, but you’d be surprised at how many people belatedly find trees and shrubs planted with the roots still in a plastic pot.

Whether it’s a non-degradable material like plastic or a material such as paper which will eventually rot, it should be removed.  Materials like cardboard boxes and pressed paper pots do rot, but they don’t rot quickly enough in our garden soils.  They impede water movement and restrict root growth.

The same holds true for burlap.  Even though burlap seems to rot readily it doesn’t rot as quickly as we would anticipate.  Some burlap is even treated with a copper material to retard decay.  Since copper is toxic to root tissues, the roots won’t grow through the burlap layer even if the burlap has decayed.  In some instances, plastic burlap is used.  That definitely won’t decay any time in the near future.

Dense Root Masses and Encircling Roots

When left growing in containers too long, many trees and shrubs develop cramped root systems, which make it difficult to grow them with success.  For plants to survive and grow, you will need to loosen the roots of those with dense, fibrous root systems.  When roots are dense and matted, cut them with a shovel, spade, or knife.  Make six to eight shallow vertical cuts into the exterior root mass.  Use your fingers or a hand fork to loosen the cut roots and help spread them out.

Another method of remedying problems with dense root masses of container grown plants is to “butterfly” the bottom of the root mass.  Use a shovel or spade to divide the bottom half of the root mass, creating two flaps or “wings.” The “wings” are kept apart by with soil, a stone, or a stick before filling the planting hole with soil.  Make six to eight vertical cuts to the exterior roots in the uncut, top portion of the root mass.

Plants with thicker, woodier roots, often develop encircling roots when grown in a pot too long.  These roots will keep growing in circles, if they aren’t disturbed at planting time.  The roots should be cut and spread as just described above.  With encircling roots the plant eventually chokes itself to death. Circling roots can’t reach out in the soil for water and nutrients needed for healthy growth and the poorly established root system doesn’t perform its anchoring function very well.

Clay Root Balls

Many quality nursery plants sold in this area are dug from nursery fields in the Williamette Valley in Oregon.  Many of these fine plants have one major drawback... the soil in the root ball is a heavy clay.  This clay is very different from local yard and garden soils.  It’s dense and holds onto water very tightly.  When the landscape is watered to accommodate our lighter, more droughty soils, the plant ends up with roots that are constantly too wet because of the clay soil around the roots -- this often leads to root rots.

One can avoid the problem by avoiding the purchase of plants with clay soil or one can try to remedy the situation by gently forking soil away from the root system and exposing the roots.

Creating a Bathtub Effect

Adding organic matter such as peat moss, compost, or mulch to the backfill soil of a planting hole is not a good.  It generally is not helpful and can create a “bathtub” effect.  Water easily enters the coarser soil in the planting hole but drains our slowly because the surrounding soil is more dense.  Again, the roots stay wet for long periods of time and root rots are very likely to develop.

However, when planting an entire landscape bed or border amending the soil with organic matter is a good idea.  Loosening the soil and adding the organic matter fosters good root growth.  Preparing the soil in the entire bed for planting eliminates the bathtub effect that can occur with planting holes.

Compact Soils

In planting sites around new homes and buildings, the soil is often very compacted.  This is especially true on commercial sites where the soil had been compacted with heavy machinery to provide a suitable area for paved parking.  Roots of trees, shrubs, and other plants have a hard time growing in compacted soil.  Water doesn’t move well into and through compacted soil.   There isn’t as much oxygen available to plant roots in a compacted soil.  Because the soil is tight, roots have a hard time penetrating the soil.

The best thing that can be done in a new planting area to relieve soil compaction is to loosen the soil by physically disturbing the soil by deep tilling or digging.

Proper Planting Techniques

1. Dig the hole deep enough to accommodate the root ball.  Keep in mind that the top of the root ball should be level with the soil or slightly above it.  The planting hole should be at least twice the diameter of the root ball.  The wider the hole, the better. Note: Always lift your tree and shrub by the root ball, not by holding onto the trunk. 
2. For balled and burlapped plants, first situate the plant in the hole and then remove all twine, string, or wire from around the root ball and stem.  Cut the burlap away from the root ball, removing as much as possible from the hole. For container-grown plants, cut and loosen roots if needed before placing the root ball in the hole.
3. Add appropriate amounts of slow-release nitrogen fertilizer to the planting hole. Backfill with the native soil you removed from the hole. Do not amend the backfill soil with organic matter. Gently firm the soil around the roots and definitely don’t tamp the soil down around the roots with your feet.
4. Water the plant thoroughly to help settle the soil around the roots.  Mulch the entire root zone area with bark mulch.
5. Keep the soil around the roots moist but not wet and saturated.
6. Prune to remove only the broken branches.  

Chlorosis — Yellow Leaves

Chlorosis — Yellow Leaves

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

Leaves turning yellow is called chlorosis. Chlorosis is an abiotic (not caused by a living organism such as a fungus or virus) disease. It's characterized by greenish-yellow to yellow leaves. What causes chlorosis? The answer isn't easy because the cause is probably not the same in every case... but there are some very likely possibilities.

Much of the chlorosis seen in this region on trees during the summer is actually iron chlorosis or chlorosis caused by a lack of iron in the plant tissues. Iron is needed for the formation of chlorophyll, the green pigment in leaves. Without the green pigment which allows a plant to utilize sunlight for production of food and energy, the plant will eventually die.

Plants with iron chlorosis first turn yellow-green to yellow between the veins, with the veins remaining a darker green. With more severe chlorosis the leaves become pale yellow and develop brown spots between the main veins. Leaf margins may also turn brown with the leaves later drying up and falling off. Tree growth slows to a stop and dieback of branches can occur when iron chlorosis is extreme.

Iron chlorosis is quite common in our area because we tend to have alkaline soil. Alkaline soils are characterized by a pH above 8.0. While our soils actually contain adequate amounts of mineral iron, its in a chemical form unavailable to the plants due to the high pH of the soil. The yellowing or chlorosis can involve the entire tree, or may be restricted to one side or even just one branch. Within the same yard, there may also be perfectly healthy green trees growing right next to ones with iron chlorosis.

Certain types of trees and shrubs are more prone to iron chlorosis than others because they're more sensitive to high pH soils. Those trees most likely to show symptoms of iron chlorosis include pin oak, flowering dogwood, sweet gum, silver maple, tulip tree, magnolia, catalpa, white oak, holly, and white pine. Acid-loving shrubs, like azalea, blueberry and rhododendron, are also prone to iron chlorosis. These types of trees and shrubs should be avoided when planting in soils where the pH is extremely high.

While it's common to encounter highly alkaline, calcareous soils in this region, a high pH is not the only cause of iron chlorosis. First of all, it may not even be iron chlorosis. Chlorosis can be confused with similar symptoms expressed by mineral deficiencies such as magnesium, manganese or boron deficiencies.

Cultural factors can also lead to symptoms of chlorosis. Over watering is probably the most common cause of chlorosis, in fact iron chlorosis can be induced if soils are kept excessively wet as a result of over watering, compacted soils, or poor drainage. Tree and shrubs in this region often develop "lime-induced chlorosis" as a result of over watering.

Chlorosis can also be the result of root damage, girdling roots, or trunk damage from mowers and weed eaters. This is because root restriction, root injury and trunk injury all impair a tree's ability to take up and transport soil nutrients.

Chlorosis can also develop in extremely dry soil situations because mineral nutrients must be in solution for a tree to be able to absorb them from the soil. In dry soils they can't absorb the nutrients. Chlorosis is often seen on large silver maples in situations where half of the root zone or more is located in an area that isn't irrigated regularly, such as a dry lot, a gravel driveway, or a ditch bank area.

What can you do about chlorosis? If the cause is excessively wet soil, adjust the watering so the it doesn't remain saturated for any length of time. You will still need to water the tree adequately so it doesn't undergo drought stress. Watering should be done slowly enough to moisten the soil to a depth of at least 18 to 24 inches without saturating the soil. If the soil is compacted, aeration may help the water penetrate the soil more quickly. If the soil is too dry, the remedy is simple... water regularly to maintain moist soil to a depth of 18 to 24 inches in the entire root zone of the tree.

If watering or compacted soils doesn't seem to be the problem, check for trunk or root problems. Look for trunk injury from physical wounds to the base of the tree from mowers or weed trimmers. See if the bark on the southwest side of the tree has been damaged from winter injury. Check for girdling roots, constricted roots, or damage to the root system. When possible, these problems should be corrected. In some cases the tissue damage can not be corrected and the tree may eventually succumb to its injuries.

Finally, correcting iron chlorosis in alkaline soils isn't an easy task. Before you do anything, it's a good idea to have a soil test to find out the alkalinity of your soil. Once you've determined that your soil is alkaline, there are several approaches you can take in an attempt to correct iron chlorosis.

One of the most simple approaches is to acidify the soil. This is most easily achieved by adding sulfur to the soil prior to planting, but acidification is a slow process and the pH change will be slow. The easiest sulfur to use is prilled sulfur. This should be applied at the rate of 25 pounds per 1000 square feet of landscape bed and mixed thoroughly into the soil to a depth of 18 to 24 inches. If trees and shrubs are already established you will need to apply acidifying fertilizers, such as ammonium sulfate, instead.

Another method of correcting iron chlorosis is the application of iron chelates to the soil. Chelated iron is less affected by soil pH and more readily available to trees. Iron chelates must be placed in the root zone by drilling holes in the soil or working it into the soil.

Iron chelates in soluble form or iron sulfate can also be applied to plants through a spray to the leaves. These foliar sprays often result in a quick "greening" of the leaves, but the effects are temporary. New growth that develops after application will still be chlorotic.

There are also methods available for injecting iron right into trunk tissues with implants or injections, but these cause wounds to the tree trunk and many arborists advise against using them.

So if your trees are turning yellow, determine the cause and take action.

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.