Why You Should Prune Your Trees in Winter

When spring comes, we think of all the things we should do in the garden, such as pruning. But winter can be a better time to prune for several reasons.

1. Pruning in winter is like having an x-ray.
In winter, deciduous trees have cast off their coverings, giving us a much better view of their structure. We get a clear picture of the entire tree, allowing us to identify weak branch connections, cracks in limbs, unsafely crossing limbs and dead wood. Winter is the ideal time to uncover and address the structural flaws that can eventually lead to branch or tree failures.

The structure of this tree is revealed by winter.

2. Winter storms are dangerous pruners.
As we unfortunately saw last month, high winds and wet snow put tremendous strain on branches. Though many branches were lost in Hurricane Sandy and the following snow storm, others still need to be removed. Additionally, broken branches should be professionally pruned so that the cut can be in the right place to promote the natural healing process that trees employ. We recommend that you identify and remove dead or cracked branches before winter does its own pruning, which can be dangerous for property, people, and the tree.

3. Your yard won’t mind.
Pruning and removing trees is easier when the ground is frozen. A tree care professional can typically move heavy equipment closer to the trees they are working on without harming lawns or herbacious perennials and annuals. Removing dead trees is often simpler when surrounding trees are bare. Plus, your family will experience less inconvenience when they’re usually indoors anyway.

4. Make spring more beautiful. Many of the flowering trees and shrubs we love, like apples, cherries, and magnolias, have already formed their buds for spring flowers by the end of fall of the previous year. By selectively pruning in winter, we can improve the saturation of flowers and fruit they have in the growing season. Winter is a busy pruning season for orchards!

Proper pruning techniques are important, whether on a shrub or tree. If you do your own shrub pruning, make sure you pick the right season for each shrub and use the proper techniques. For example, pruning early flowering shrubs now (like azaleas) will lead to fewer blossoms. Our local Cornell University Extension has an excellent free guide to pruning that you can download  “An Illustrated Guide to Pruning Trees and Ornamental Shrubs” here.

Before you prune your own trees, make sure you understand proper pruning techniques. Correct pruning, whether to remove dead wood or to improve a tree’s structure, is much more than just picking a spot and sawing away: the placement and execution of a proper cut actually helps the tree with its healing process.

When trees require pruning of high branches or a power saw is needed, it’s time to call a professional. A professional tree care company (and of course I include Almstead), has the right tools, equipment and safety training to do the job.

How Trees Respond to Drought

A Longleaf Pine showing the effects of drought.

Although we all know that trees need water, scientists are still discovering new information and implications about the process that allows trees to “drink.” Thanks to recent scientific research, we now have a greater insight into the mechanism of tree death from drought and a new appreciation of how vulnerable trees are.

Trees draw water through their roots and into the thread-like channels of their vascular system that distributes it to their most remote needles and leaves. In order to photosynthesize and grow, trees need to open the stomata (pores) on their leaves to take in carbon dioxide. As they do this, water evaporates. The water loss creates a suction effect that goes down all the way to the roots, where the water is replenished, similar to drinking through a straw.

When water is unavailable, this suction pressure increases, and air is drawn in. The air bubbles clog the channels and make it harder for a tree to get fluid to its leaves – like drinking from a broken straw. This “hydraulic failure” is the reason trees die from drought.

In addition to hydraulic failure, drought can impact a tree’s ability to open its stomata. Even when water is again available, some leaves are unable (or slow) to return to their work of photosynthesis, causing further dieback.

Dr. Brendan Choat from the University of Western Sydney and Dr. Steven Jansen from Ulm University in Germany lead a team of scientists that have studied hydraulic failure in trees worldwide. The results of their research show that about 70% of tree species have very little margin in the amount of drought they can endure before they experience hydraulic failure. Surprisingly, this was true for species that grow in marsh as well as desert. The implications of this research are that a small change in the drought level of an area could have serious consequences for large numbers of trees.

Watering trees in times of drought is extremely important. Even the largest tree typically has its roots concentrated within the top 12” of soil. They have no ability to suddenly find water when that layer is dry. Trees will respond to drought by dropping leaves or needles, and then having whole branches die. The damage can be irreversible.

Sophisticated systems are now available to monitor the moisture content of soil and automatically adjust watering to the appropriate level for plants, lawns or trees. These irrigation systems are now common in arid regions and have been found to reduce total water consumption. Giving trees the right amount of water at the right time can prevent hydraulic failure and also prevent the unnecessary waste of water in landscapes by up to 60%. I believe we’ll see this technology introduced in the northeast over the next decade as water for our landscapes becomes a more precious commodity.

Hurricane Sandy Is Still Causing Damage

Looking up at these trees, you can see
that one is leaning dangerously.

The last two weeks have been among the toughest of the 20 years I’ve been an arborist. The combination of the hurricane, the snowstorm and the broad and long-lasting power outages is unlike anything I’ve encountered before. All of us at Almstead have had too many opportunities to witness the violence of nature, as we’ve removed hundreds of trees that have damaged houses, cars and other property.

Although Sandy has passed, the damage is ongoing. We’re still receiving calls from people who have trees or branches falling, or threatening to fall, from the damage caused by the storm. This is a good time to take a walk around your property, looking up. Many trees have cracked branches that need attention: some need to be removed before they fail, while others with minor stress cracks can be saved by cabling. It’s also important to check that any previously installed cables are still in place.

Follow-up pruning may be needed for branches that snapped or were improperly pruned by an emergency service. When pruned correctly, trees usually create a natural barrier against decay; improper pruning leaves a wound that is much more likely to lead to further problems. You should also look for any trees that have shifted root plates or other signs of movement.

As we work to clean up the damage caused by Hurricane Sandy, we’ve noticed that many of the fallen trees and branches had defects that probably would have been identified by a qualified arborist. So don’t panic and start removing all the trees from your property; while it’s true that no tree is guaranteed against the violence of a hurricane, healthy, well-pruned trees have amazing resilience. The trees on your property have shown they can survive a hurricane! With a little attention, they will probably continue to provide beauty and shade for another generation or more.

Arborists are trained to identify tree problems before they occur, which is just one reason to have a certified arborist inspect your trees. This is a good time to contact an arborist to inspect your trees for any potential problems.

--Ken Almstead, CEO and arborist

Salt Damage to Turf and Trees

One of the effects of Hurricane Sandy was coastal flooding. The result is that many areas of turf and trees have been either submerged in salt water or deluged with salt spray. While coastal plantings are usually salt-tolerant, many areas further inland have received a dose of salt that can be toxic to grass, plants and trees. The effect of salt is so damaging that it was used as a weapon in ancient times to destroy an enemy’s crops.

When the soil’s salt content increases, roots find it harder to take in water. At elevated salt levels, water within the root can actually be drawn out of the plant, causing wilting.  Neither sodium nor chlorine is generally good for plants (trees take the small amount of chlorine they need from the atmosphere).  The sodium will displace essential nutrients like potassium, calcium, and magnesium, making them unavailable to the plants. At the same time, the roots take in the chloride ions and transport them to the leaves, where they accumulate and interfere with chlorophyll production and photosynthesis.

Grass damaged by sea salt

“The solution to pollution is dilution” is an adage that is appropriate here.  Since salt is water soluble, it can be further diluted and washed through the soil by adding more water. Water your turf and plantings until the soil can’t absorb any more, wait for it to drain completely, and then water again. Keep it up until the ground freezes.  

If your Almstead turf specialist suspects that there is too much salt to be eliminated by dilution alone, he will probably test the soil to determine the level. If the salt level is too high, we usually add gypsum to the soil through core aeration. We also have organic amendments containing humates that can speed up the process. With early action, the effects of Sandy’s salt water bath should be mitigated by spring.

Protecting Your Evergreens with Antidesiccants

Rhododendrons respond to cold weather.

Many of you with rhododendrons in your yard can tell the temperature outside by looking at the droop of their leaves. Rhododendrons are highly thermotropic plants: their leaves move in response to the temperature. As the thermometer falls the leaves begin to droop and curl; when the temperature goes well below freezing, the leaves are tightly curled and pointing straight down.

It’s hard to believe that these leaves will unfurl and rise again in response to warmer weather – but shrubs and trees are remarkably resilient. There are times however, when they can use some extra help.

As winter approaches, I recommend applying antidesiccants (also called antitranspirants) to most broadleaf shrubs. This is not a remedy for the curling leaves of your rhododendron – those leaves are supposed to curl and actually help the plant survive the cold. The stomata (the tiny holes on leaves that allow the escape of moisture) are tightly closed, preventing any moisture loss. The problem for broadleaf evergreens is not the cold, but the warmth. When a winter thaw occurs, your rhododendron leaves will straighten out, rise up and start sweating (actually transpiring). Because of the frozen ground, the roots may not be able to replace this water loss. Add some chilly winds, and the moisture loss can be dramatic. This is where leaf damage and loss -- and even plant death – may occur.

The antidesiccant adds an additional oily or waxy coating to the leaves, keeping the moisture inside. Many evergreens in our area are especially vulnerable to winter damage, particularly holly, rhododendron, cherry laurel, skip laurel, mountain laurel, Japanese skimmia, leucothoe, aucuba and boxwood. I recommend using an antidessicant on these plants in early winter. We try to spray the plants with antidessicant on a dry day when there’ll be no precipitation and the temperature is above freezing (around 40 – 50 degrees is good); you shouldn't apply the spray in freezing temperatures.  It's important to coat both the top and undersides of the leaves. Antidesiccants are typically organic and biodegradable; they will wear off the leaves by spring.

Rose canes and hydrangea stems will also benefit from the spray, as will young trees with thin bark. Some evergreens with needles do not need antidesiccants; plants like arborvitae and spruce can actually be harmed by it, or at least lose their blue color.

When a winter thaw occurs, as often happens in our area, another coat of antidesiccant will help the evergreens stay hydrated until spring.

-Ken Almstead, CEO and Arborist

Post Storm Cleanup

Anyone who has trees – and a few who don’t – is now faced with post-Sandy cleanup. While you’re surveying the trees and branches that have fallen on your property, don’t forget to look up. As you clean up your yard and get back to pre-storm life, it is important to carefully scrutinize the surrounding trees.

These crossing branches can indicate a
shift in one of trees.

Many branches that snap off in the wind don’t make it to the ground right away. They can be hung up on the lower branches of a tree or powerlines. These branches could drop to the ground because of a gentle breeze, a frisky squirrel, or just the passage of time. If branches are hanging on an electric line, stay clear and call your electric utility. If they are in a tree, stay clear and call Almstead.

Look at your trees carefully. Has there been any shifting? If you are familiar with your trees, you may notice a change in their outline against the sky. Take a good look at the roots for any sign of upheaval. If a tree’s balance has shifted, it could fall without the aid of a hurricane. Sometimes stress cracks will appear that make the tree vulnerable to failure. Also, any tree that has been cabled or braced should be checked to see that everything is still intact. An annual inspection by an arborist is always a good idea, but it is even more important after a major storm.

This cracked soil indicates a shift in the roots. 

It is often necessary to follow up storm damage with additional pruning. Branches that have been snapped or ripped off – or incorrectly pruned by an emergency service – are much more likely to decay. Following up with proper pruning cuts is better for the health of the tree.

When cleaning up after the storm, we don’t recommend that you use a chainsaw unless you are trained and are wearing protective clothing: our tree crews wear glasses, gloves and chaps. Chainsaws are dangerous even in experienced hands; there is always a danger of the log or the saw springing back. Our advice is to call us to cut up any large branches or fallen trees. 

Leaves: Move 'em or Mow 'em?

Norman Rockwell: Grandpa and Me Raking Leaves

All the beauty of autumn eventually lands on our lawns. Pleasant childhood memories of jumping into piles of leaves are quickly supplanted by the drudgery of raking them -- or herding them with a leaf blower. Yet there is another option: mowing them.

If you have deciduous trees, you have leaves falling – often a lot of them. Whether you manage them yourself or hire someone to take care of them, it’s time for all of us to think about how (and where) we dispose of our leaves. Most of our communities here in Westchester have leaf recycling programs.  We put our leaves by the curb, either loose or in bags, and local government collects them. Some communities have a facility for turning the leaves into mulch or compost onsite while others truck the leaves away to larger facilities that are often hundreds of miles away.  

The cost of leaf collection and disposal is causing many of us to question whether we’re spending money and squandering resources in order to get rid of something that is actually valuable – leaf mulch. Many communities are discussing whether to stop collecting leaves entirely, a move that would improve their budgets. (Leaf collection can cost a municipality hundreds of thousands of dollars.) Several university studies have demonstrated that mulching leaves in place does no harm – and may do a lot of good.  Mulching leaves returns nitrogen to the soil; lawns need nitrogen to be green.  If you currently apply nitrogen to your grass, mulching will allow you to use less.

Mulching mowers have become increasingly common both for do-it-yourselfers and for lawn care companies; these mowers were designed to return grass cuttings to the lawn where they decompose and return their nutrients to the soil. The mowers do a good job of shredding leaves as well, with the same results.

So how do you begin? Start mowing. Studies show that, even when mulch is piled 4 to 6 inches high, the lawns do well.  It’s safe to say that our lawns will usually benefit from as much mulch as all the trees in our yards can produce. If the mulch is so deep that the grass isn't poking through though, it’s probably time to redistribute it.

As you probably know, different trees have leaves that differ in their chemical makeup, for example oak leaves are more acidic than maple. One of the benefits of mulching with a mower is that the leaves are shredded where they fall: beneath the tree that grew them and will benefit most from their decomposition.

One place where you may have to take out the rake (or the blower) is your perennial bed. If your bed is bare for the winter, you can wait until the first hard frost and then mow right over it. More typically though, our beds include shrubs or perennials that have attractive winter forms: for these locations, you’ll need to remove the leaves, shred them and then pile them back on. A thick layer of leaf mulch on these beds will help to insulate them from temperature fluctuations over the winter. It’s important to shred the leaves rather than leaving them whole, however, because a thick layer of whole leaves will inhibit growth.

Whether you choose organic or traditional lawn care, leaf mulching is a good strategy. The shredded leaves nourish, insulate, keep the grass greener longer, reduce the need for soil amendments, increase beneficial microbial activity and actually make the turf feel springier. So you improve your lawn, help the environment and save money. 

--Ken Almstead, CEO and Arborist

High Flying in Manhattan: Removing a Backyard Tree by Crane

A property management company for whom we've done a number of difficult jobs, inherited a large dead tree when they took over a new location. They called us to remove the problem.

A neighbor later told me that the tree had been dead for 4 or 5 years. Because of the tree's condition and location (in back of a row of brownstones in the Upper West Side), traditional forms of removal were not an option. So, we hired and worked with a 40 ton crane. The crane was parked on the street in front of the building; from there it could reach over the top of the buildings into the back yard and hold, and then lift, sections of the tree over the buildings.

A neighbor later told me that the tree had been dead for 4 or 5 years. Because of the tree's condition and location (in back of a row of brownstones in the Upper West Side), traditional forms of removal were not an option. So, we hired and worked with a 40 ton crane. The crane was parked on the street in front of the building; from there it could reach over the top of the buildings into the back yard and hold, and then lift, sections of the tree over the buildings.

There was a problem with trying to remove this tree using traditional methods. Usually, we would use the main part of the tree as an anchor to support and lower pieces as they were cut. The cut pieces are dropped from their location until they are caught by the rigging we install. But at the moment they are caught, there is stress put on the trunk of the tree. If the stress is too great, the trunk will break and the whole tree -- climber included -- will come crashing down. We couldn't take that chance with this tree. The climber was able to tie sections of the tree to the crane, make the cut, and have the crane bear the weight away. This way there was no shock to the trunk.

We do crane removals frequently, but this is the only one I have seen or heard of in the city where we had to reach over the top of a posh brownstone!

-- Chris Busak, Arborist

Transplanting 6 Tons of City Trees

Weekends are quieter than weekdays in Manhattan’s financial district – 

Early Saturday morning: pruning to reduce the 

canopy size and improve the overall 

branch structure.

so that’s the best time for moving a tree through the crowded city streets. Trane Construction Company at 55 Water St. needed to make some renovations to their site which would displace two large Callery Pear trees. A new location was chosen at a public school on the island side of the Manhattan Bridge.

Work began on Friday night when a crew came in to break up and remove the sidewalk cement surrounding the trees. The City of New York would allow for the closure of the sidewalk only until 7 p.m. on Saturday, so the pressure was on!

Our Almstead crew began early the next morning, painstakingly digging a trench around the base of the tree, excavating 5 feet down to get as much of the root structure as we could. We knew what the size of the new sidewalk planting pit would be, and pruned the roots to form a root ball as large as possible. City trees rarely have the luxury of developing an extensive root system; they struggle to survive under adverse conditions. Our job was to give these trees the best start possible in their new location.

We also pruned the trees so the canopies would be smaller – making less work for the smaller root structure. We wrapped the root balls in burlap and tied them to keep them intact. We also gently tied the canopy together to prevent damage on the journey.

Digging out a tree. Because of the existing 

curb 2’ from the trunk, we elongated the root ball 

to retain as much root mass as possible.

Then we brought in heavy construction equipment to lift the 6,000 lb.trees from their holes and carry them to their new home. We took them on a 25-block journey through the streets of Manhattan – past the South Street Seaport, under the FDR Drive – accompanied by an NYC Dept. of Parks and Recreation escort.

We placed them in their new holes and filled in the remaining space with high end compost, specialized soil, organic biostimulants and additives to increase water retention in the soil and promote healing and rooting. Finally we covered them with a 4” layer of hardwood mulch to further protect them from temperature fluctuations and inhibit moisture evaporation from the soil.

We’ll be stopping by every 2 to 3 days to make sure the trees are well watered and not showing any ill effects from their journey. We have designed an ongoing Plant Health Care program for the next two years to give these pear trees the best start possible in their new home. We hope to see them thrive in front of the school.

-       Chris Busak, Arborist

Unwanted Pest #1: Bronze Birch Borer

We have gotten to the end of our list of the Most Unwanted Insects. For #1 we chose the Bronze Birch Borer (Agrilus anxius).

Why did we choose the Birch Borer for the #1 spot rather than the insects that can destroy an entire tree species? (i.e. the Emerald Ash Borer or the Asian Longhorned Beetle)  Because it’s HERE. NOW.  And because, as arborists, we’re dealing with damage – often fatal -- from this insect all the time.

We all love birch trees. The bright, white, striped paper bark birch is often the first tree we recognize as children. As an understory tree, white birch can light up the forest. Seeing a birch grove in the snow is breathtaking. And other birches, such as river birch with its curling peek-a-boo bark revealing a salmon-colored trunk, are popular planting choices as well.

The problem with birch is that they are really not meant for our landscapes.  Under the best circumstances, birch trees don’t have lives as long as most of our other trees. And our yards and parks are not the best of circumstances. Birch trees grow best in slightly acidic, moist, well-drained soil.  They like sun on their faces but not on their feet. They don’t like pollution. When they don’t have the right conditions, they become stressed; this makes them more vulnerable to both insects and disease. The attacks of insects like the birch leafminer and aphids or diseases like rust and mildew further compromise the tree’s health.

This is where the Bronze Birch Borer comes in. The Birch Borer lays its eggs beneath the bark of the birch tree – and prefers to have its path cleared by another insect or other damaging agent  first. So Birch Borers rarely attack healthy trees, but can be deadly to trees already experiencing some decline.

As the Birch Borer larvae emerge they ravenously eat the underside of the bark, gouging out galleries as they munch. These channels cut through the phloem of the tree, interrupting the tree’s ability to transmit water and nutrients.

Larva and gallery of the Bronze Birch Borer
Source: David G. Nielsen, The Ohio State University, bugwood.org

Because the larvae grow beneath the tree bark, often the infestation goes unnoticed until the tree canopy starts to yellow, at which time it can be too late to save the tree.  It takes aggressive treatment to halt an attack of Bronze Birch Borers. In an infested tree, the trunk can be injected with a control that can help to stop the larvae from developing. The trunk can also be sprayed with a substance that helps to prevent new insects from colonizing the tree. The correct treatment depends upon the health of the tree, the degree of infestation and the time of year.

Not all birch species are equally vulnerable to Bronze Birch Borer. The River Birch, in particular, seems to resist the insect, while the Silver Birch is particularly susceptible. Ultimately, the best way to prevent the Bronze Birch Borer from killing your trees is to keep your Birches as healthy as possible.  Birches need deep watering  -- weekly, at least.  Although the leaves need sun, the roots must stay cool, so a layer of ground cover or mulch will help to insulate them from the heat.

We recommend checking Birch trees frequently for signs of pests and disease. Any yellowing leaves or dieback could indicate a potentially fatal problem; early intervention can sometimes avert a fatal infestation.

Unwanted Pest #2: Asian Longhorned Beetle

We’re almost to the end of our series on the Most Unwanted Garden Pests. This is villain #2: The Asian Longhorned Beetle (ALB).

The ALB (Anoplophora glabripennis) doesn’t live in our area (Westchester, Bergen and Fairfield counties) – yet. And hopefully, it won’t. Intensive eradication efforts are ongoing in New  York City, Long Island, Massachusetts, Union and Middlesex counties in New Jersey and Ohio, the areas where ALB is currently residing. The USDA is taking an aggressive approach to this mission – any tree infested by ALB is cut down and burned.

Why is the ALB so despised? Because of the deadly outcome of an ALB infestation and the extensiveness of their diet.  In our area, we’ve had several species of trees virtually eradicated by insects or disease over the last century: the American Chestnut by chestnut blight, the American Elm from Dutch elm disease, and – currently – several species of ash trees from the Emerald Ash Borer. But the Asian Longhorned Beetle has the potential to decimate several widely growing tree genera in our area, including maple, birch and sycamore. In addition to the loss of these beautiful trees, the economic impact on our hardwood forests would be immense.

The story of the ALB’s infiltration into the U.S. sounds like a spy movie. Someone notices a suspicious looking insect. They call a government agency. The insect is identified as a stowaway assassin from China. Soon after, the Feds swoop in and destroy the insects along with any possible hiding place. They search the neighborhood looking for more insects and any possible shelters – and in a slash and burn frenzy, cut down any trees that could harbor these terrorists.

Yet this dramatic response seems to be yielding results. The ALB appears to have been eliminated in the Chicago area, and it looks like New York and New Jersey may soon follow. Massachusetts is still battling hard and finding new ALB hideouts.

The USDA’s Animal and Plant Health Inspection Service (APHIS) actually acts like Homeland Security for invasive pests. They have intercepted ALB in warehouses in California, Florida, Illinois, Indiana, Massachusetts, Michigan, North Carolina, New Jersey, New York, Ohio, Pennsylvania, South Carolina, Texas, Washington and Wisconsin.  And their Canadian counterparts have intercepted the ALB in several provinces there. 

Asian Longhorned Beetle Exit Holes
Source: Kenneth R. Law, USDA APHIS PPQ, Bugwood.org 

One thing that works against the ALB is its size and striking markings. The beetles are over an inch long and colored like a Mardi Gras mask. In several cases, an ALB was identified when someone saw it and said, “What IS that thing?”  When a tree is infested with ALB, the exit holes can make it look like it’s been strafed with a machine gun.

Right now, the best chance we have of defeating the ALB is public awareness. So if you see a large, gaudy beetle, call for backup! This USDA site will give you more information: http://beetlebusters.info/ (It’s worth visiting just to see their CGI beetle!)

Unwanted Pest #3: Hemlock Wooly Adelgid

If you have hemlocks in your yard, you probably already know of the Hemlock Woody Adelgid (HWA). This tiny aphid-like insect has been attacking and killing hemlocks throughout the eastern United States.  The devastation it causes makes it #3 in our countdown of Most Unwanted Landscape Pests.

Both the Carolina Hemlock and the Eastern Hemlock are victimized by the Hemlock Wooly Adelgid. This insect doesn’t restrict itself to weak or stressed trees – healthy trees can be infested as well. Although a tree can survive an attack from the HWA, continued infestation is deadly, robbing the tree of the needles necessary for survival.

There are no preventive measures for HWA; hemlocks should be inspected frequently for signs of infestation. You aren't likely to see the adelgids:  they are so tiny they are almost imperceptible. But the signs of their presence are unmistakable: little dots of cotton appear along the base of the needles where they meet the wood. These cottony blobs are protecting the HWA eggs. When the crawlers emerge, they will latch on at the base of a needle and start draining the hemlock of its vital fluids. Obviously, a single adelgid doesn’t drink much; but as the population grows, the cottony balls extend along every branch, harboring millions of thirsty adelgids. Within a few years of infestation, the hemlock is usually dead. Some of our beautiful, native hemlock forests have disappeared because of this foreign invader.

Hemlock with wooly adelgids.
Source: John A. Weidhass, Virginia Polytechnic Institute
and State University, Bugwood.org

Fortunately, this is an insect that we can successfully battle. Both foliar sprays and systemic controls are available that can give us the upper hand against these insects. There are several factors that should be considered in order to determine the best course of treatment, such as the size of the tree, the extent of infestation, soil and weather conditions and proximity to streams or ponds. Your Almstead arborist will evaluate how these factors impact your hemlock and propose a method for combating these evil adelgids.

In the future, there may be biological controls for HWA. Currently, experiments with predatory insects and fungi look promising, especially for forests where the cost of treating individual trees is impractical. For now, careful monitoring and early action are the best safeguards against Hemlock Woody Adelgid.

The Secrets of Compost Tea

Michael Almstead, August 9, 2012. 

The Compost Tea Workshop was held on the beautiful 

campus of Rye Country Day School.

Last month, Almstead had the opportunity to conduct a workshop on Compost Tea and Air Spading for the Northeast Organic Farming Association (NOFA). Arborist Dan Dalton and I, along with compost tea brewing specialist Russell Wagner and lawn technician Marc San Phillipo and several other Almstead professionals, really enjoyed being able to share our knowledge and experience with others interested in organic tree and plant care.

The workshop was intensive. We covered both the science behind Compost Tea brewing and the practical issues and hurdles to creating a brewing business. I’ve been involved in Almstead’s evolution into organic care from the beginning and believe that products like compost tea are win-win: healthier for the lawns and trees as well as the environment, friendlier to consumers, and safer for everyone.

Continual aeration is a necessity for compost tea.

Brewing high-quality compost tea is an involved, scientific and careful process. Compost tea is NOT a slurry of compost and water. It must be carefully balanced to meet the nutritional requirements of the plants it’s meant for.  It contains living organisms that have to be kept alive through constant aeration – both while the tea is brewing and in the truck delivering it.

Russell Wagner microscopically checks our Compost Tea

 for the proper microorganisms and fungi.

We have a mini science lab in our Compost Tea brewing facility, where we examine everything going into the tea. We want it loaded with beneficial organisms, both bacteria and fungi; we add them, and make sure they are live and happy (and in the proper proportions) in the tea before we apply it. We also make sure that no damaging organisms are sneaking into our mixture.  This quality control is vital to brewing compost tea – without it, you’d  just be delivering a truckload of dirty water.

We have a rather substantial Compost Tea brewing operation here at Almstead. Compost tea is an organic way of adding nutrients and microorganisms to the soil – sort of a jump-start for soil to rejuvenate itself, making it more attractive for worms and other beneficial organisms, and keeping the process of soil development going. And it dramatically cuts down the use of chemicals, a plus for both for the environment and for people who are exposed to their lawns.

Dan Dalton describes the nutrient cycle.

Dan Dalton taught the segment on soil properties. He emphasized the necessity of understanding the chemical, physical and biological elements of soil in order to create a compost tea – sometimes augmented by other organic amendments – that facilitates the right soil profile. This goes way beyond simple pH – it includes factors such as adjusting the particle size of soil components and encouraging symbiotic fungi that help keep damaging organisms away from tree roots.

We create different teas for lawns and for trees because of their varying requirements. Lawns need a higher ratio of bacteria, while trees require more fungi. For large locations (like a college campus or business park) we can create a Compost Tea based on soil testing. Sometimes we add specialized ingredients like nematodes or mycorrhizal fungi to meet their specific needs.  We talked in general about recipes for compost teas – but the formulae that Almstead has carefully developed for our clients remains a closely-guarded company secret.

The participants examine fibrous roots exposed
by air spading.

Our NOFA presentation also included a demonstration of air spading. Air spading (using compressed air to loosen soil around tree roots) is a wonderful tool of organic tree care. There are several methods we can choose from, depending upon the results desired. Essentially, by using the air spade, we can loosen and/or remove compacted soil. We fill in with looser soil and amendments, allowing the tree roots to “breathe,” encouraging them to grow and giving them easier access to the nutrients and water in the soil.

Russell performed air spading on one of the Rye Country Day School campus trees. Since fibrous roots are concentrated in the top 8” of soil, compaction can deprive a tree of both oxygen and nutrients. First , he excavated the critical root zone around the trunk, easing soil compaction and allowing examination of the roots for signs of girdling or disease; then he air spaded out radially from the trunk (like slicing a pie).  These slices were filled with compost and other soil amendments to provide the roots with easy access to oxygen, water and nutrients.  

Marc San Phillipo demonstrates soil injection 

of compost tea into the root zone.

Mark San Phillipo also demonstrated the soil injection of compost tea into the root zone. Compost tea can also be used as a soil drench.

By the end of the day, the workshop participants seemed to leave with a new appreciation for these important tools in organic plant care.

-             --- Michael Almstead, Vice President & Arborist

Unwanted Pest #4: Scale

Our reverse countdown continues. #4 in our list of the most Unwanted Landscape Pests is Scale.

Scales are tiny insects, less than ¼”, that do almost nothing – except suck the life out of plants. There are 7,000 different types of scale insects, broadly divided into armored and soft.

Scales live boring lives. A female insect attaches herself to a leaf or shoot and begins to feed. She lays eggs beneath herself (some scale insects mate while others can reproduce without outside help) and provides shelter while they develop. “Crawlers” emerge and start to seek out their own locations. After a few days their mobility is over: they hook onto a plant and begin sucking -- forever.

Woolly Pine Scale
Source:  Terry S. Price, Georgia Forestry
Commission, Bugwood.org

  Although immobile, scales have protection. Armored scales create a hard protective covering, basically a shell. In fact, some scales are referred to as oyster shell, while others look like small pearls. Soft scales are covered in a waxy coating; they often appear as fuzzy white dots of fluff on a plant. Most release fluids as they suck; this sticky “honeydew” can cause even more problems by attracting other insects or mold – and dripping on anything below.

Scales are so tiny that they are rarely noticed until the population has increased to troublesome size. But, en masse, they can harm or even kill plants – even trees. Their lack of mobility causes them to feed in ever-increasing numbers on their host plant.

Scale’s armored or waxy coating makes them difficult to kill. They are only vulnerable to insecticide sprays during their brief crawling stage. Thorough drenching in horticultural oil or insecticidal soap can also combat scale. Finally, systemic treatments are available that cause the tree to repel the feeding insects.

Magnolia Scale
Source:  Brian Kunkel, University of Delaware, Bugwood.org

There is no single treatment for scale insects – nor do all scale insects need to be removed. Almstead arborists and technicians examine every tree to determine the most appropriate treatment, based on factors including the type of scale, the stage of development, and the size of the tree. 

Most Unwanted Pest #5: Elm Bark Beetles

Our reverse countdown of the 10 Most Unwanted Pests continues with #5: the Elm Bark Beetle.

Elm Bark Beetles are mass murderers, responsible for the devastation of the American Elm population – up to 99% of elms have succumbed in some areas. Once the go-to urban tree, the rows of stately elms that lined our streets and shaded our parks have disappeared due to the Dutch Elm Disease transmitted by these beetles.

European Elm Bark Beetles (Scolytus multistriatus) and the Native Elm Bark Beetle (Hylurgopinus  rufipes) make their home – and their meals – beneath the bark of trees. The beetles penetrate the bark and bore through to the sapwood. Once inside, they gouge out galleries for their eggs. The larvae develop beneath the bark of the tree and expand the galleries to eat the underside of the bark.

The hungry Elm Bark Beetle larvae gouge out
these galleries as they feed.
Image: Joseph O'Brien, USDA Forest Service, Bugwood.org

 

Unlike most bark beetles that target soft-wood trees, the Elm Bark Beetle targets the hard-wood American Elm. The beetles typically lay their eggs in elm trees that are already weakened or beginning to decay. This means that Elm Bark Beetles would never have made our Unwanted list on their own: their larvae rarely do substantial damage to a healthy tree, and controls are available to fight these infestations. It is the adult Elm Bark Beetle that is causing so much such fatal damage. Although most of their lives are spent in weak trees, they fly to feed on healthy trees as part of their life cycle. They carry the fungus that transmits Dutch Elm Disease from the failing tree to its healthy neighbor.

Once the fungus enters the elm tree it starts to clog up the tree’s xylem – the aquaduct system inside the tree. The tree responds by trying to seal off the infected xylem tubes with its own clogging mechanism: this is why one of the first signs of Dutch Elm Disease is a yellowing patch of canopy as a branch stops providing water to it.

Elm tree branches affected by Dutch Elm Disease.
Source:  USDA Forest Service - Northeastern Area Archive,
USDA Forest Service, Bugwood.org

Can Dutch Elm Disease be stopped? Not currently. But individual trees can be maintained in good health for a long time – and a fortunate few never succumb. The first step in prevention is keeping elm trees healthy. Beetles are most attracted to trees that are already stressed, so a regular program of watering and fertilization is important.  Dutch Elm Disease also spreads less quickly in a well-watered tree – greater hydrostatic pressure can help slow it down.

There are also inoculations that can slow the progress of Dutch Elm Disease. The earlier the better.  So it’s extremely important to monitor elm trees for any signs of infestation or canopy yellowing. In the early stages, pruning can remove infected branches before the disease spreads to the rest of the tree.

Finally, if you have an elm tree that is beyond saving, it should be removed immediately. The wood must be disposed of appropriately and the stump removed. The roots should also be severed if other elms are near, to prevent the disease spreading through root connections. 

Unwanted Pest #6: The Evil Weevil

Number 6 in our countdown of America’s Most Unwanted garden pests is the Black Vine Weevil.

The Black Vine Weevil (Otiorhynchus sulcatus ) is a root feeder. Although adults will damage foliage, the most serious damage is done by larvae feeding on roots. The insects’ diet includes hundreds of shrubs and ornamentals, including yew, hemlock, some rhododendrons and other broad-leaf evergreens like azalea, mountain laurel and euonymus. Adults can also feed on deciduous and herbaceous plants.

When shrubs fail to put out new foliage in the spring or new foliage quickly yellows or dies, one of the first suspects is this evil weevil. Another indication is the characteristic crescent notches on the leaf margins made by adults feeding. The adults are active at night throughout the summer. The non-flying insects are about  ½” long, slate grey to blackish-brown with pitted wings and a short snout.

Prevention and Control

One important step to prevention is carefully examining new plants before bringing them home. Since adult insects are unlikely to be seen, the leaves should be checked for signs of damage.

If you begin to see leaf damage on your shrubs – or stunted growth – call your Almstead arborist for an inspection. Often, by the time the damage is noticed, the plant’s health has been seriously compromised.

Biological controls for Black Vine Weevil are beginning to be available. Nematodes (little organisms that make weevils look big) are ingested by the weevils; they then execute an Alien-worthy switch and kill their hosts. Although this biological control is promising, chemical controls are presently the usual choice for dealing with these pervasive pests. Treatments are most effective on adult populations before they begin to lay eggs. That puts the timing of treatments around late May, with repeat applications through the summer if necessary. (These weevils can have several generations per summer.)

If you didn't treat for Black Vine Weevil this year and are wishing that you had, consider a fall treatment to reach overwintering larvae, which are found in the soil.

Unwanted Pest #7: Aphids

#7 in our series on America’s Most Unwanted garden pests is the all-too-common aphid. Aphids otherwise known as plant lice, are tiny soft-bodied, sucking insects. With over 4,400 types of aphid worldwide, they are the most common garden pest. Most aphids only target one kind of plant, while others have a much broader diet.

These tiny (1/32”) pear-shaped insects can be winged or wingless and almost any color. A colony of aphids can cause substantial damage to plants, trees and shrubs including yellowing or curling leaves and stunted growth. In addition to sucking the juices from plants, their saliva is actually toxic to many plants. Aphids often transmit fungi and disease to the plants they infest. 

Aphids with their ant bodyguards
Source: E. Bradford Walker, Vermont Dept. of Forests,
Parks and Recreation; Bugwood.org

In the process of feeding, aphids secrete a sticky, sugary liquid called honeydew -- which can rain down from the trees on anything below it, like your car or lawn furniture. Given the size of an aphid, when there’s enough honeydew to drip from a tree, you know that there is a huge population feeding above.  

The sweet honeydew is attractive to ants. Many sugar-eating ants actually act as body guards to aphids: they protect them in order to milk the aphids for honeydew. In addition to the damage aphids cause directly, the honeydew can make plants more susceptible to fungi, like sooty mold.

Potato Aphids
Source: David Cappaert, Michigan
State University:Bugwood.org

Inspecting plants for aphids is the first step towards controlling this pest. Many aphids are well camouflaged to blend with the plants they target. Their coloring – along with their tiny size – means aphids are often overlooked until they are so numerous that they coat the plant. Aphids are a preferred food of beneficial insects like ladybugs, predatory wasps and lacewings; a sufficient population of these species can keep aphids under control.

If aphids have populated a plant or shrub, a stream of water from a garden hose can sometimes dislodge them; although flying aphids are likely to return, crawling ones often won’t make it back to the plant.

Because of the potential damage from aphids, as well as the diseases they transmit, it is wise to begin controlling aphids at the first sign of infestation. Almstead arborists offer both organic and traditional methods for control. Often a single application in spring is sufficient to keep aphids in check.

Most Unwanted Pest #8: Tent Caterpillars

Our countdown of the Most Unwanted arbor pests continues with #8: the Eastern Tent Caterpillar (and a similarly domiciled pest, the Fall Webworm).

Although many insects can be difficult to identify – or even detect – the tent caterpillar is not. One day you look at your tree and notice that something has actually pitched a tent there. The tent looks like an industrial version of a spider web: thick, white and slightly opaque. If you look carefully, you may see the newly emerged caterpillars celebrating their good fortune.

A single tent is not an infestation – yet. But often, if you continue your examination of the tree, you’ll find that it’s turned into a caterpillar campground. An infestation of tent caterpillars can defoliate – or eventually kill  –  a tree.

These insects are native to our (NY/NJ/CT) region. The larvae emerge in spring and construct a tent for their dormitory. They emerge daily to feed on the leaves of their host tree. Their favorites are black cherry, choke cherry, scrub apple and many species of ornamentals in the family Rosaceae (including serviceberry, hawthorn and many more).

A tree with several colonies of eastern tent caterpillars can be completely defoliated by the hungry grazers. Most trees can withstand this for a single season, but a repeated assault can leave the tree without the resources to survive. 

For a residential tree, the unattractive appearance of caterpillar tents and the resulting defoliation are reason enough to try to remove the pests. For a smaller tree, Almstead arborists can selectively clip off the egg masses in the fall, or remove the caterpillar tents in spring. For a large tree, it is more practical to apply a control to prevent the larvae from emerging.

Just as tents in your tree in spring usually indicate tent caterpillars, similar tents in the fall are usually a sign of Fall Webworms.  Black cherry is their preferred tree but they are also common on alder, apple, beech, birch and oak.

Fall Webworm Damage
Courtesy of  Ronald F. Billings, Texas Forest Service, Bugwood.org

In June and July, moths lay their larvae on the underside of leaves and cover them with scales. As the larvae grow, they eat the leaf tops; the tents are expanded as they move to new branches. It’s possible for the tent to envelop an entire tree and for the webworms to defoliate it completely.

The webworms don’t typically kill trees, since trees have already stored up most of their nutrients by the time the defoliation occurs. However, the effect can be grotesque. Your Almstead arborist can discuss alternatives for shutting down the tent city in your tree. 

Unwanted Pest #9: Japanese Beetle

This is the second villain in our countdown of the Top 10 landscape pests in our area:

Beautifully glowing with green and blue iridescence and coppery wings, the Japanese Beetle doesn’t look like it should be despised.  But Japanese Beetles have earned their unsavory reputations by having populations that quickly grow out of control and damage almost every part of our landscape.

And summer is Japanese Beetle time: this is when the adults emerge from the ground and start dining on our plantings. With a diet that includes over 300 different plants, our yards are their buffet. They devour the soft leaf tissue of our plantings, often leaving only the leaf ribs behind. Since July is also their time to mate, a few Japanese Beetles can turn into a mob when they release pheromones that attract other beetles from a mile away or more.

In late July through August, the females lay their eggs in our lawns. It takes less than two weeks for the larvae to develop into grubs and start gnawing their way through the grass roots. These grubs are the single most damaging lawn pest we have.

There are a few different ways to control Japanese Beetles. Certainly the simplest is to remove them by hand -- and if the beetles have confined themselves to a single rosebush, it’s possible to curtail their population this way. However, if they’re munching through your Birch tree – or you have no interest in hand-picking beetles – you probably should consider a more sophisticated solution. We usually recommend applying a low-toxicity spray to the most susceptible plantings, repeated 2 or 3 times over the course of the summer.

The grubs represent a different challenge. Because Japanese Beetles are very mobile, it’s possible to have lots of grubs beneath your lawn, eating the grass roots and creating dead brown patches, without seeing many adults. We have several options for treating grubs. When we confirm grub activity (we do this by lifting the soil and looking), we can apply a grub treatment. One annual application usually controls all kinds of grubs, including Japanese Beetles.

There is also a purely organic approach that targets only Japanese Beetles.  Milky disease is caused by a bacterium that infects Japanese Beetle grubs. We can apply Milky Spore powder to a lawn to control the Japanese Beetle grub population.  The Milky Spore continues to infect the beetles for several years.

One warning: many sources sell pheromone traps for Japanese Beetles. These traps work well – at attracting Japanese Beetles to your yard from all around the neighborhood. So don’t buy these traps – unless they’re a gift for your neighbor!