Fall Web Worm

Photo K. Fosty

The fall web worm is a gregarious fellow who likes to get together with friends and eat your prized fruit tree or ornamental. Fall is the time of year when these caterpillars pitch their tents and throw a feast! However, with our climate the French name for these lepodopterans is Chenille à tente estivale, “worm who puts up a tent in the summer time” seems a bit preemptive.

Hyphantria cunea is common all over North America but in it's most northern range, Canada, it only manages to get in one life cycle per year. The insects over winter in pupae attached to fallen leaves and emerge in the spring as adults. The adults mate and then the females lay their eggs on the underside of leaves covering them with silken threads. The eggs hatch and the party begins, munching their way through foliage at an alarming rate. While they eat they excrete silk to create a protective nest. They can often be seen grouped together in their nests early in the morning or on cold days. Typically the host plants for these indiscriminate feeders includes, apple trees, balsam poplars, choke cherries, pin cherries, trembling aspens, white ashes, white birches, white elms, and most willows.

Typically the damage is mostly cosmetic, especially when you consider that the trees have already gotten some energy from the leaves and within a few weeks of lose them. These insects rarely eat all the leaves on a tree and seem to only enrobe a branch or two for their harvest festival.

If you have the stomach for it you can remove the nest by hand or with snippers in the morning and eliminate the problem. They are susceptible to a number of control methods including insecticidal soap or strong stream of water. Check the label on your product of choice or contact a professional to clean up these insects. Cutting out the webs when they are young is the preferred method, and be sure to bag them and dispose off site. A few hours in a black plastic garbage bag in the sun will eliminate any chance of them surviving. Tie the bag tight as they will try to escape and as I found out set up shop in the trunk of your car! If you thing you have this gregarious group dining on your prized specimens contact your Certified Arborist.

Fall Planting Tips

Fall is unfortunately the forgotten season for planting.

Spring, the traditional time to plant, is the busiest, most crowded time to visit your local nursery. Many trees can be planted in the fall and the prices at the nursery can be very reasonable.

I received a call the other day from a valued client who was thinking of replacement plantings for a few trees taken down over the last few years. A quick consultation over the phone started the process to selecting the right trees. We were able to get together at a nursery and chose two trees that suited both the site and his vision of the landscape.

We were also able to avoid trees that would cause problems in the planting locations further down the road. When looking for the right tree it is important to consider the growing conditions at the site. Three major considerations are shade tolerance, drainage and soil conditions. There are many trees that do well in partially shady locations, few that do well in deep shade and many that require full sun to grow and thrive.

Growth habits of the tree are very important when considering the final location. A tree that grows into a large shade tree should not be planted to close to buildings. Trees that produce

flowers are great to use a focal point in the garden during their flowering season. Be sure that the fruit they produce doesn't become a nuisance by dropping onto your patio or deck. Fighting with wasps and flies or constantly washing your fruit stained deck is not a lot of fun.

Some flowering trees produce no fruit and still provide you with great colorful flower displays.

There are trees that retain their fruit and provide wildlife a valuable food source through the winter. Watching winter birds gather fruit and seeds can break up a grey winter day.

Once you have your choices, more are better, go to the nursery and carefully examine their stock .

All trees are not created equal, or at least they don't end up growing that way. Even among cloned cultivars there can be tremendous differences in branch structure as well as cultural artifacts that you may want to avoid. We are not talking about shards of ancient pottery in the growing media, what I am referring to are the various issues that may be present in the nursery that will cause problems later. Trees that have groups of roots spiraling around the base of the tree should be avoided, pot bound trees will fail in future years. While you are looking at the roots look at the base of the main stem, does it have scars or damage from old injuries? This could cause rot at the base of the tree resulting in failure. Following up the trunk look for branches that are co-dominant or have included bark. If you want a tree that has a strong single leader avoid ones that have large branches separating low down on the main stem. Take a close look at the amount of growth present this year and in past years. You can do this by looking at the length of this years growth back to previous years bud scars on the branches. Trees that seem to be growing less each year should be avoided.

Generally younger smaller trees will establish quicker and last longer in the landscape than a larger mature tree. Once you have found a tree that best suits all your needs and have checked it for faults its time to negotiate the price and planting details with the nursery. Selecting good trees right from the start is the best way to ensure great trees in the landscape. If you have more questions about tree selection and planting contact your Certified Arborist.

Soil Gas

Land Fill Without Trees

Soil gas is often the forgotten member of the the soil composition trilogy. While the solid and liquid proportions get all the attention the soil atmosphere is often left literally up in the air.


Soil consists of 3 primary components solids liquids and gases. The solid components take up approximately half of the total soil volume and consist mostly of minerals and a small percentage of roots, plants, and animals referred to as the organic component. The other half of soil consists of even amounts of soil water and soil atmosphere.
While the solids and liquids perform obvious functions like support and nutrient transport, soil gases are more nebulous in their critical relationship to tree growth.
This need for air should be second nature to us all as we share the need for oxygen with our green friends. Without oxygen there is no life and gas exchange is critical to all plants. While
green photosynthetic tissues give off oxygen they also give off carbon dioxide when they burn energy to create chemicals and perform life processes. This process is called respiration and we animals do this part ourselves. Roots and stems do not normally photosynthesize and respire almost exclusively. They need and ample supply of oxygen and good gas exchange to keep everything in order.
Presence of oxygen is the reason that 80% of all tree roots are concentrated in the upper ten inches of the soil.
The arch enemy of soil gas exchange is soil compaction. Soil compaction reduces and can even eliminate small pore spaces in soils. Without soil pore spaces fresh air can not enter the soil and sour gases from decomposition or plant waste processes become toxic to tree roots. Tree roots will often be seen growing at or close to the surface of the soil. More than a futile attempt to anger the lawn mower, this is an indication of compacted soils. Soils that are saturated with water also force tree roots to grow closer to the soils surface. Excess soil moisture can exclude soil gases and eliminate root activity. This is what happens in the classic case of killing with kindness by over watering potted plants. The same thing can happen to trees and shrubs in our landscapes.
The composition of soil atmosphere can have a beneficial or detrimental effect on root activity. Loose porous soils exchange gases like carbon dioxide, created in root respiration and allow for fresh oxygen laden air to reach actively growing roots. Benificial mychorizal fungi benefit from the presence of oxygen and depend on gas exchange to thrive.
When soil moisture levels are high, oxygen levels become low and tree roots die and decay. Roots decaying with out oxygen give off toxic gases like methane that further injure living roots and soil organisms.
In some instances buried or decaying vegetation or construction debris in the sub soil can give off toxic gases that kill roots. Yards that are built on fill or with soil that has been deposited on existing vegetation when grades were drastically altered can slowly decompose. Decomposition gasses are the primary reason that trees are seldom seen growing on old landfills. If you have more questions about soils and soil composition contact your Certified Arborist.

Verticillium

Few tree diseases rival Verticillium for sheer tragic loss. Unfortunately it often appears first thing in spring and the initial indication of its presence is a dead or dying tree. This disease effects a number of tree species but is very commonly the demise of maples. When it comes to maples this disease isn't picky, it can wipe out a prize cut leaf weeping Japanese maple or a weedy box elder without warning. Ash, some linden, buckeye, and russian olive can also fall prey to this potentially fatal disease.

Verticillium dahliae is a soil born fungus that invades the trees vascular system. The disease enters the trees vascular system from the roots and moves upward in the xylem as spores. Toxins produced by the disease and the trees response to the fungus results in wilting symptoms. Very often a tree will be infected with this disease and recover, losing only a branch or two. However later on when when put under stress the tree may be overwhelmed and fail completely. The disease persists in the soil for up to ten years as highly stable fungal structures. Once an area is known to have verticillium it is recommended to plant resistant replacement plants. Generally burr oak, apples, birch trees, walnuts and most conifers are resistant to this disease.

The typical symptoms mimic other vascular fungal diseases like Dutch elm disease, flagging and wilting of leaves and branch die back. In fact the field diagnosis for verticilium is cutting a branch and looking for staining in the sap wood just under the bark. Positive identification in the field should be followed up with a confirmation by a laboratory. In the lab they will put chips of the diseased sample on a petri dish and grow it to confirm the presence of the disease. In elm trees the filed sampling can sometimes result in confusion, but verticillium generally isn't fatal in American elms. Dutch elm disease however is fatal 99% of the time in non resistant elms. Of 100 elm trees sampled and showing staining of the inner bark, less than 2 will have verticillium the remainder will have Dutch elm disease and will be dead by the time the lab results get back to you. I have sampled the same elms several years in a row, with the lab results coming back positive for verticillium consistently. Some of these trees are still standing. In contrast to elms in maples the first sign of verticillium is often slow stunted leafing out in the spring. When this overall infection is present the tree will most likely fail with in weeks and simply dry up and die.

There is a strong correlation with root disturbance and the onset of verticillium infection. It is not recommended to dig tunnel or cut roots near maple trees. Incidence of this disease is low in natural stands. Once a tree has verticillium it is impossible to eliminate it from the tree or soil. Fungicides are ineffective in treating this disease. Maintaining the vigor of the plant is the best plan of action. Fertilizing with a low nitrogen high potassium fertilizer with added beneficial bacteria and root stimulants is of benefit. Generally this should be done as a soil drench and not as a deep root injection. Root injection may result in additional root injury and should be avoided on trees susceptible to verticillium. Trees under moisture stress are more susceptible to verticillium. Wood chips from these trees should be composted and allowed to heat up before using them in landscapes. If you think your tree may have a problem contact your certified arborist.

The Big Dirty

A Novices Guide to Tree Planting

As a young Scout I had the good fortune to plant trees on the east side of Riding Mountain. Many years later while working in the area I was able to locate the area where we had planted and marvel at the forest that was growing in the rough pasture.

The instruction we received was “ stick in your shovel and before you pull it out, put in your seedling”. It was a good thing we were planting trees by the hundred because our success rate was pretty low. If you are planting trees and want to be successful here are a few tips that will increase your odds.

Keep your tree moist,

Never let your trees roots dry out well planting. Roots take up moisture by osmosis, they have no control over evaporation and when left in the sun they will dry out quickly and die.

Dig a big hole.

Always make sure you loosen a large area of soil to allow your tree room to grow. A good hole is wider than deep. The depth depends on your root ball, or root depth if you are planting bare root trees. Your roots should never bend up out of the hole like a “J”. The roots should spread out on the bottom like an upside down “T”

Use the soil you took out of the hole to back fill the the tree

Mixing a little of the soil from the root ball into the back fill encourages the roots to venture beyond the root ball and into the planting site soil.

Make sure the sides of the hole are not glazed.

If you rough up the edges of the planting hole you will have more success and less circling roots. Digging with spade or a power auger can result in a glazed, root resistant planting site.

Never plant your tree too deep.

Make sure the first branch is well above the original soil surface and the first root is at or just slightly above the original soil level. You can lay your shovel across the top of your planting pit to make sure you are above grade. Tree roots seldom grow upwards and planting too deep is often a slow death sentence.

Cover your roots well.

Place the soil around the tree once you plant it and gently push it into place to reduce the amount of air around the roots.

Water your trees after planting.

Watering trees right after planting sorts out the pore spaces in the soil and ensures that the roots will be in contact with soil moisture. This greatly increases the chances of survival.

Ask your Certified Arborist

Arborists are experts in tree selection and tree planting, a quick consultation will help to ensure your success. If you are ever driving on Mountain Road you may catch a glimpse of my “ Trees for Tomorrow !”

Subtle Art

Pruning trees and shrubs is a subtle and evolving art.

While we could spend many pages debating the intricacy of bonsai or the angles of espalier, we should focus on everyday pruning.

Many times when I have properly pruned a tree a client will comment “it hardly looks pruned”. I always take this as a complement, and will explain the cuts and the rationale behind each one. When I first took my tree pruning license, the rule of thumb was no more than 33% of the crown in any one pruning session. Although it was a while ago that I took my tree pruning exam and I'm sure I wasn't number 007, I did have a license to prune. Fortunately most of the pruning was done by hand and the amount of over pruning was limited by your own strength.
It matters little if you use a bucket truck or climb the tree if you do not have a sound knowledge of the tree and its growth habits and the results of pruning it. Modern equipment increases the potential to do great harm to trees.
The 33% maximum amount pruned has been reduced to 25% and this is stressed as the extreme maximum. On more than one occasion I have suggested that the tree should be removed if you really don't want any of the branches or leaves on it. Truthfully there are some trees that are in the wrong place and may need to be removed. However if you love trees and see the great benefit that they provide, a small amount of pruning will help these giants to live with you.
Returning to the problem of over pruning, if your tree ends up looking like an ancient Greek statue you probably have missed the point when it comes to pruning. The amount to prune is always a concern for the skilled arborist. Many times potential clients will suggest doing radical cuts and extensive pruning that would undoubtedly result in damage or death of the tree. Unfortunately people seem to think that by over pruning they can get better value by avoiding future cuts. I call this the “ pound of flesh “ concept, as in “If I'm gonna spend the money, I want to see a pound of flesh”. This logic would work if you were carving stone or chopping concrete into small rocks. Trees are living dynamic organisms that contribute ascetically to our environments. The living tissue you remove is essential to the tree to create and store energy. Unfortunately the more you prune the more the tree will respond by putting out new and often uncontrolled growth. Any amount of pruning injures the tree and will create a response from the tree, managing these responses is the real art. One should always discuss the reasons for pruning and the expected results at great length with their arborist before you decide to prune. Once you have removed a branch it will never grow back and restoring form may be difficult.
Prune little, prune often is a better strategy in the long run. A few select sell placed and performed cuts will always be better for your pocket book and for your trees.

Sex and the Sycamores

While you may not be able to grow sycamores or ginkos in your garden, some understanding of the complexities of tree gender expression may help to avoid messy problems in your yard.

I used to enjoy visiting a friend's verdant garden in Brentwood. She would walk around pointing out the new trees and shrubs assigning genders more or less randomly. “ That viburnum she's not happy, he's shading her out” and then my hostess would point up to the large box elder that towered over the viburnum. Judging by the seeds on the box elder I knew this wasn't entirely true. When in this situation there is much to be learned by simply listening. After a few visits I discovered that more than assigning genders, my host was personifying the trees as they were literally part of her family.

Trees express gender in a variety of ways. Typically genders are assigned by the presences of male or female flowers. Male flowers produce pollen and female flowers produce seeds. If it were that simple this would be a very short article.

Flowers on trees and shrubs can be male, female or both. In which cases the plant would be better referred to as an “It”. To further complicate matters some species of trees have individuals with only male flowers, clearly “He” trees. The same species will have trees with only female flowers, clearly “ She” trees. This same species will have a small percentage of trees that have male and female flowers on the same individuals, clearly “It” trees. Given that this may account for up to 15% of the individuals of the species it is clearly not a random mutation, rather a part of the overall genetics of the species.

While this may be a surprise, you won't have to go far to find these strange exotic trees.

Ash trees, maples, and yes sycamores all have this type of gender expression. It can be a nuisance and even an major problem if you have a seed bearing tree in an area where the seeds are not welcome. Some trees, like crab apples can be down right dangerous when they are to close to walks or patios. Slipping and falling on decomposing apples can be more painfully than getting stung by a wasp disturbed from its apple sauce dinner. If you have ever had the misfortune of stepping on the ripe fruit of a ginko tree

you will remember the pungent odor. Fortunately plant breeders have used their knowledge of plant anatomy to develop varieties that are based on male cultivars.

This ensures that you have the landscape tree you want without the seeds that may cause trouble. “Baron” maple is a good example of a seedless male cultivar of Box elder.

If you are planning on planting trees this spring, consult your certified arborist they will help insure you get the best tree for your location.