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Archive for the trees tag

Mulch volcanoes are harmful to trees—here’s why.

April 18, 2023 • Leave a Comment

by Steve Turner

Mulching is one of the best things you can do for your plants if it is done right, but too much or improperly installed mulch can be a real problem.

The problem

The common practice of mounding mulch against the trunk has proven to be a fatal one for many trees. These often seen “mulch volcanoes” are perfect circles 8 to 12 inches thick (or more) piled against the trunk. They are actually creating more problems than they are solving.

What compounds the problem is that many of these trees are on commercial properties under professional care, and this has helped create the false impression that this is the proper way to mulch trees. Homeowners see this and imitate the practice on their own trees. The neat, clean appearance it gives a landscape is appealing to many. Actually, I have had several customers over the years ask me if there is a mold they can buy to make these volcanoes on their own trees! So in our quest for a beautiful landscape, we are unknowingly sacrificing the long-term health of the trees.

LEFT: Mounding mulch against the trunk of a tree can create problems, including wounds, decay, and girdling roots. RIGHT: Mulch should be placed in a ring around the tree, with the center around the trunk empty, like a wide doughnut. — **LEFT**: Mounding mulch against the trunk of a tree can create problems, including wounds, decay, and girdling roots. **RIGHT**: Mulch should be placed in a ring around the tree, with the center around the trunk empty, like a wide doughnut.

How does it harm trees?

The bark on the roots of a tree is much different than the bark on its trunk or branches. It is able to tolerate moisture as well as the lower oxygen levels in the soil. The aboveground portion of the tree, which starts at the root flares, has bark that contains tiny openings which are used to release gases and toxins from its system. On plants such as cherry trees or forsythias, these sites (called lenticels) are easily seen as tiny white dots or dashes on the bark. Because of this important function, trees can’t tolerate soil or mulch placed above its root flares. The lack of air and the presence of excess moisture prevents natural respiration from the bark and causes a build up of gases and toxins in the bark tissue.

The damage

If soil or mulch disrupts the respiration of the bark, the tree will usually respond in one of two ways. On thin-barked, young trees or species with naturally thin bark, like beech or linden, this disruption causes cankers (wounds) on the trunk. These appear as areas of dead tissue and provide an opportunity for decay to enter the tree. Other species will react by sending out additional roots from the trunk. These roots often end up circling around the trunk and become girdling roots in the future. Researchers are finding out that trees with girdling roots and excess soil and mulch build-up are much more prone to snapping off at the base in wind and ice storms. The longer the problem exists, the more damage occurs, and the chances of correcting it decrease.

Note that not all trees will respond in the same way—species, age, and health all need to be considered when trying to evaluate the effects of past damage. Most willow trees, for example, are very adaptable to a change of grade and often will show no problems at all.

Can the problem be fixed?

If caught soon enough, it can be corrected and tree will recover. However, upon root crown inspection, if it is found that large cankers have formed and decay is present, or if the tree has developed extensive girdling roots, it might be wiser to remove and replace the tree than attempt to save it. During the root crown inspection, arborists use a high pressure air device called an “air spade” to safely remove the excess soil and mulch without damaging the root system. Once the soil is removed, there is a clear view of the buried trunk and roots. Then the damage can be evaluated, and a decision made as to which roots to leave and which can be safely removed. It is very important not to remove too much too soon or the tree will be shocked. Sometimes the work will have to be done in stages over a couple years.

Proper mulching

While it is common to see 4 to 6 inches of mulch around a tree, this is usually too much. I would suggest 2 to 3 inches placed in a ring around the tree with the center around the trunk empty, like a doughnut. How wide to make the ring is up to you, but the bigger the better. Trees don’t like to compete with lawns for nutrients and water, and the more mulched area you can give them, the better off they will be. Mulched trees have fewer problems than trees growing in lawns. Even a small, 2- to 3-foot ring can make a big difference. The mulch creates a more natural growing environment with its organic material breaking down and supporting vital soil microbes. Other benefits include increased moisture retention and cooler soil temperatures, both of which favor optimal root growth.

If done properly, mulch is a great asset to your landscape and aids your trees during summer drought periods by maintaining soil moisture. It also helps insulate the roots during the winter months, which allows them to remain active longer through the seasons.

Steve Turner, Certified Arborist, is from Arboricultural Services (248-259-8420).

ELSEWHERE: Mulch overload!

How do you select the right tree care company?

June 20, 2022 • 1 Comment

**This mature oak tree provides plenty of shade. (Photo: tsg pixels)**

by Steve Turner

How do I select the right tree care company? Many times when I’m out on consultations, the homeowner will tell me they have had their trees sprayed, but the problem is still occurring. Or the trees were trimmed, but the crew apparently did not notice a particular pest or disease. How come? This is not always an easy question to answer, but most times it will be that the company just didn’t know or that the situation called for expertise beyond what they offer.

There are basically three types of tree care companies and knowing what their capabilities are should help you decide which type is right for you.

Type #1. The first is the lawn and tree care company that fertilizes your lawn and offers a basic program to spray your trees 3 or 4 times and fertilize them each year. This is a popular option with homeowners because it is fairly inexpensive and the homeowner is already familiar with the company. The drawbacks are that the sprays are done when the company is scheduled to be in your area and, as a result, may not always be timed to treat the specific problems that you might have. Insects have complex life cycles and the timings can vary year to year as to when the best time to treat them is. If you miss this “window,” many treatments will be ineffective and the problem will persist.

These types of companies are fine for covering the basic care in a cost-effective manner. For more serious problems or more advanced treatment, it is advisable to turn to the other two company types.

Type #2. The second type is the company that specializes in pruning and tree removal only. There are more of these than both of the other types combined. There is a wide range, from the weekend warrior with a chainsaw and a pickup truck, to the large company with a fleet of bucket trucks. Choosing between them can often be difficult, because it is not always easy to assess their skill levels until after the work is done. Getting references is important, especially if it is a more complex removal over a house or trimming a large, 100-year-old oak tree. You want the most skilled and knowledgeable tree care professionals to do these types of jobs because you only get one shot at getting it right and there is little room for error.

Asking a few simple questions and paying attention to how they write an estimate can help you determine their professionalism. First and most important is, are they insured? Second is, do they use spikes to climb trees that are to be only pruned and not removed? Unfortunately, protecting your trees from unnecessary damage is not always the top priority of some companies. These two questions can help forewarn you of potential problems.

Next is the written estimate they give you. How much detail do they put into the contract? Are they vague in describing what they intend to do or do they provide a clear description? Can they identify all the species of trees they will be working on or do they just write “large tree in front yard?” The more detailed the estimate is, the less likely you are to be disappointed with the results of the job. The quality of work performed by these types of companies can range from excellent to poor—make sure someone in the company has a good knowledge of proper tree care. There is a big difference in knowing how to climb a tree and knowing what to do once you’re up there. Overpruning is a common problem of some tree companies; every tree needs to be evaluated on an individual basis in regards to its species, health, and age to properly determine what needs to be removed and how much.

Type #3. The third type of company is the complete tree care service that offers a full range of tree care treatments, from fertilization to difficult removals. They will tend to have educated professionals on staff, highly skilled climbers and ground workers, and trained plant health care technicians to identify your problems and treat them. There are probably 20 to 30 of these types of companies in the metro Detroit area and many started out as one of the other types and grew into full service. These companies will tend to have affiliations with professional associations in our industry such as the ISA (International Society of Arboriculture) or the TCIA (Tree Care Industry Association). Look for these logos when hiring a tree company to help ensure quality work.

When writing estimates, they will tend to use ANSI standards to describe the work to be done. This is a national system of defining common tree pruning terms that all can understand and interpret the same way, in order to avoid misunderstandings and variances in services. Examples of these terms would be “crown clean” or “deadwood” to describe what will be removed from the tree. “Elevation” will specify to what height the tree will be raised, such as “10-foot elevation over house.” All these things help make it easier for the homeowner to understand what will be done, as well as receive competitive bids for the same level of work.

Most tree care companies bid by the time it will take to do the work and the amount of equipment needed to do it safely. Most will charge based on their hourly rate and the type of work, and then add on wood removal costs. Full-service companies tend to charge more for their services because their overhead is higher as well as their payroll to attract top professionals to their companies.

It is not advisable to automatically pick the lowest bid to do the work. Often, the lowest bid will also be the least experienced and knowledgeable company. Some might use spikes to climb your trees or take shortcuts that could damage your lawn or landscape. Just remember to keep in mind that you get what you pay for.

Steve Turner, Certified Arborist, is from Arboricultural Services in Fenton, MI.

Scientists estimate there are about 9,200 undiscovered tree species

March 1, 2022 • Leave a Comment

**Coniferous mixed forest, Val Saisera, Italian Julian Alps, Italy. (Photo: Dario Di Gallo, Regional Forest Service of Friuli Venezia Giulia, Italy)**

University of Michigan: A new study involving more than 100 scientists from across the globe and the largest forest database yet assembled estimates that there are about 73,000 tree species on Earth, including about 9,200 species yet to be discovered.

The global estimate is about 14% higher than the current number of known tree species. Most of the undiscovered species are likely to be rare, with very low populations and limited spatial distribution, the study shows.

That makes the undiscovered species especially vulnerable to human-caused disruptions such as deforestation and climate change, according to the study authors, who say the new findings will help prioritize forest conservation efforts.

“These results highlight the vulnerability of global forest biodiversity to anthropogenic changes, particularly land use and climate, because the survival of rare taxa is disproportionately threatened by these pressures,” said University of Michigan forest ecologist Peter Reich, one of two senior authors of a paper scheduled for publication Jan. 31 in Proceedings of the National Academy of Sciences.

“By establishing a quantitative benchmark, this study could contribute to tree and forest conservation efforts and the future discovery of new trees and associated species in certain parts of the world,” said Reich, director of the Institute for Global Change Biology at U-M’s School for Environment and Sustainability.

For the study, the researchers combined tree abundance and occurrence data from two global datasets—one from the Global Forest Biodiversity Initiative and the other from TREECHANGE—that use ground-sourced forest-plot data. The combined databases yielded a total of 64,100 documented tree species worldwide, a total similar to a previous study that found about 60,000 tree species on the planet.

Read more from U-M…

Can I grow ivy groundcover under trees?

February 16, 2022 • 1 Comment

We have a beautiful 32-year-old maple tree in our backyard and a city locust tree on the boulevard in the front yard. It is difficult to grow grass under both trees. If we planted ivy as a groundcover, would it hurt the trees if it climbed up them? My neighbor had some voracious vine grow up his mountain ash and the tree died.

The age of your maple tree suggests a large trunk and root flare with heavy shade. Turf grass needs sun and water, both of which the maple tree takes first with its mature canopy and characteristic surface root system. Give up on growing grass under it. Apply two inches of composted mulch between the root flares out to the canopy drip line. Keep the compost and mulch away from the trunk and off the root flares. You can then “pocket plant” shade-tolerant perennials like hosta and liriope, which will grow comfortably in those conditions, offer seasonal bloom, and give you an interesting, low maintenance groundcover.

One can grow grass under a locust although they too are shallow-rooted. If you thin out the canopy to allow more sunlight to reach the ground, a shade turf seed mix can work if the area is properly prepared. However, a boulevard takes heavy abuse from vehicles and weather. You may be better off applying the mulch method to the locust as well. The liriope is both sun- and shade-tolerant and will handle some road salt applied in winter. There are also creeping junipers that hug the ground and give you conifer presence all year. The key is to plant away from the tree trunk.

Any kind of climbing ivy is difficult to control. Their accelerated rise within a tree’s canopy crowds out the tree leaves. The tree loses its food production source that feeds its roots, which in turn feed the branch scaffold. The tree literally starves and dies, as witnessed in your neighbor’s yard.

Janet’s Journal: Gardeners and builders, save those trees

July 2, 2019 • 2 Comments

Builders are not tree specialists and may not even know the full effect of construction on a landscape. Unless you explain and enforce concepts such as the fragility and extent of a root zone,work will expand into that zone. — Builders are not tree specialists and may not even know the full effect of construction on a landscape. Unless you explain and enforce concepts such as the fragility and extent of a root zone, work will expand into that zone.

Here are tips to help you preserve your landscape during a remodeling or construction project

People are digging in these days.Not digging into the soil to make a garden, but digging in on their property to improve it by adding on or remodeling their homes. Ironically, this often increases the property value in one way while reducing it in another, unexpected way.

I’m talking about established trees and landscapes, overlooked assets that are often lost during and after construction. Sometimes, the loss is unavoidable. Even if you wanted to preserve a particular tree or group of shrubs during the construction process, it might not be possible. More often, the loss is the result of oversight, ignorance or miscommunication.

The loss can be huge, in tangible and intangible forms. First, there’s resale value to consider. Surveys by realtor groups (involving photos of homes with and without trees and shrubs) asked how much prospective buyers would pay for the various properties. The surveys indicated that landscaping can add 20 percent to the value of a home. Greenery in general, but large trees especially, garnered positive responses.

Then there are living expenses and quality of life. Energy conservation studies have proven that shade trees can significantly reduce heating and cooling costs. Environmental research concludes that established plants can cut noise levels and improve air quality, with attendant reduction in medical costs and stress-related illness for residents. And although numbers may never be able to convey the value of peace of mind, a majority of people agree that it comes in increasing amounts with beautiful surroundings filled with butterflies and birdsong.

Finally, communities lose when landscapes are degraded by construction. Many cities and regional authorities are dedicating public funds to the quest for cleaner water and lower water treatment costs. Such campaigns focus on educating the public about how actively growing, diverse plantings promote water quality by intercepting, holding and biologically filtering rain that would otherwise pick up pollutants as it runs along pavement and hard-packed soil.

It’s in your best interest to hold onto both the direct and indirect returns your landscape provides. Building professionals are not skilled in tree and landscape preservation. If you’re planning to build onto your home or remodel, or you aim to build new and want to keep all or part of the landscape, you must learn how to be an effective advocate for your trees and other greenery.

There are five points in the construction process when you should think and act to preserve your landscape. When you first consider construction, at your first serious meeting with a building contractor, just before construction begins, during the work and after the building project is complete, there are things you should know and do.

When the general public is polled,we learn that an established landscape can increase a home’s value by 20 percent… — When the general public is polled, we learn that an established landscape can increase a home’s value by 20 percent…

…to a gardener, the landscape may count for more than the house!

When you first consider construction

Your role as a landscape advocate begins when you first consider adding on, remodeling or building new. Begin by identifying “must save” plants. Then hire an arborist and/or a horticulturist, or train yourself to evaluate the health and replacement cost of those trees as well as the adaptability and moveability of shrubs and smaller plants. Get a written estimate of the replacement value of plants and detailed plans for protection and after care. It’s an invaluable item, both for your consideration as you weigh construction options and costs, and as a means to increase builders’ awareness and respect for the landscape.

You or your arborist/horticulturist consultant should also prepare a map of your property that shows the location and extent of the root zones of plants to be saved. You’ll use this to direct construction traffic and deploy protection for these invisible, surprisingly fragile and irreplaceable elements of your landscape.

Pamper “keeper” plants right from the start. Don’t wait until the plant has been damaged—for some damage is almost inevitable during construction. Fertilize your plants and begin or maintain a good watering program to build their stamina.

If you can’t protect most or all of the root zone, it’s not realistic to have that plant on your “keeper”list.This is especially true of species that are intolerant of root disturbance,such as this 70- year-old beech.The root zone extends to and beyond the tree’s drip line.Less than one-third of that area was protected. The tree died within the year. — If you can’t protect most or all of the root zone, it’s not realistic to have that plant on your “keeper” list. This is especially true of species that are intolerant of root disturbance, such as this 70-year-old beech.The root zone extends to and beyond the tree’s drip line. Less than one-third of that area was protected. The tree died within the year.

Discuss all grade changes before the fact. Excess soil piled in the root zone and against the trunk are almost certain death to a tree.The tree also suffers crushed and broken roots from the equipment which spread that soil. — Discuss all grade changes before the fact. Excess soil piled in the root zone and against the trunk are almost certain death to a tree. The tree also suffers crushed and broken roots from the equipment which spread that soil.

Deciding which trees to protect and placing barriers and cushions are good first steps toward preserving the landscape.Don’t slip up on the followthrough. If you hide your head in the sand during construction your precautions can fail.This oak’s protected root zone was breached and the soil there compacted. When the grade beyond was raised, water couldn’t drain. The tree died in two years. — Deciding which trees to protect and placing barriers and cushions are good first steps toward preserving the landscape. Don’t slip up on the follow-through. If you hide your head in the sand during construction your precautions can fail. This oak’s protected root zone was breached and the soil there compacted. When the grade beyond was raised, water couldn’t drain. The tree died in two years.

At the first planning meeting with your builder or work crew

Identify and stake out the exact placement of new buildings or structures. Determine where the grade will change and how much, whether it will be built up or cut away. Discuss all trenching and excavating ahead of time, in detail. You and your landscape experts need this information to plan specific protective measures and negotiate changes in building plans.

List all work functions that will take place on your property and where each will occur, including material storage, fuel storage, parking areas and places where paint and concrete will be mixed or dumped. Compare this to your keeper plant list and root zone map.

Plan a mutually agreeable vehicle and equipment route into the work area. Aim for a straight route, since every turn of equipment means more churning of soil and increased risk of scrapes and bumps to nearby plants. Allow for a track at least eight feet wide, as anything less represents an unreasonable expectation.

All trenching and excavation should be planned for minimal impact on “keeper” plants.Help your builder understand the effects and explore options. A trench for utility lines detoured around this oak, unfortunately, cutting through at least half of the roots along the outer edge of the circular root zone. — All trenching and excavation should be planned for minimal impact on “keeper”
plants. Help your builder understand the effects and explore options. A trench for utility lines detoured around this oak, unfortunately, cutting through at least half of the roots along the outer edge of the circular root zone.

A less intrusive option is to trench straight toward the tree and then bore under the main roots and trunk.Builders may not think this is necessary or possible since as non-gardeners they imagine the roots to be very deep.Here the main roots are visible at normal depth, within the top 18 inches of soil. — A less intrusive option is to trench straight toward the tree and then bore under the main roots and trunk. Builders may not think this is necessary or possible since as non-gardeners they imagine the roots to be very deep. Here the main roots are visible at normal depth, within the top 18 inches of soil.

When you make a root zone map of the property,you can deny access to the root zone of individual “keeper”plants. Sometimes it’s better to fence off entire areas, as here where root zones are protected behind this construction fence. — When you make a root zone map of the property, you can deny access to the root zone of individual “keeper”plants. Sometimes it’s better to fence off entire areas, as here where root zones are protected behind this construction fence.

Now you may have to modify your “keeper plant” list. Be realistic. You may have to change some plants’ status from “keeper” to “remove,” “move to save,” “keep but cut back,” “tie back,” etc. Then, for every plant that remains on the list, plan ways to protect not only the visible parts but the soil and roots. An eight-inch depth of mulch has been proven to be more effective in protecting the soil from compaction and roots from crushing than any other construction site device, including heavy plywood “paving.” Discuss this with the builder along with tarp coverage beneath material storage areas and where falling debris is expected, and where you will accept the greater cost but lesser damage to plants that comes from drilling beneath root zones rather than trenching through them.

Finally, before any work begins, discuss and list who will be responsible for plant removals and obtaining necessary permits (many communities require tree removal permits). Establish who will execute plant moves, when they will be done and how all parties will know that the involved areas are “all clear.” List, too, who will be in charge of putting up and maintaining protective fencing and padding, creating the cushioned vehicle and equipment route, and explaining all of these features and their importance to workers. Expect to be an active player throughout construction.

When construction is about to begin

Now it’s time to move, elevate or cap sprinklers, prune or tie back at-risk trees and shrubs, prepare the vehicle route and place fences and protective devices.

On the access route, peg down landscape fabric first. Its presence will confirm the original grade when it comes time for clean-up. Have eight inches of mulch dumped on the route, beginning at the entrance with successive truckloads rolling over already-mulched ground.

Place fences and barriers. Keep two things in mind as you do this. One, if there is space, workers will use it. Two, people need room to work. It’s true that work expands to fit the available space, so barriers are necessary, but they must not hamper the work.

Post signs, even if you feel they are redundant or obvious. “Fuel storage,” “dump excess concrete here,” “stay out, loose soil” are some messages you want to communicate clearly.

Expect to pay extra to protect plants and soil. The construction industry is not aware of its full impact on plants, does not go back to see the consequences years later, and has not been asked to consider the cost of effective protection in its estimates. So be prepared to buy or pay extra for tarps to cover paint mixing areas, “bulldog” type porous tarps to protect shrubs from falling debris or paint, and increased labor to carry in rather than truck certain materials across the soil.

During construction

Your most important act during construction is to stay involved. Many gardeners have described how they felt the need to detach themselves, to avoid looking at what was happening in their yard, and afterward go through a process of reclaiming the space. This is understandable but precisely the wrong thing to do.

Get out there, every day, to see what’s happening, to communicate with the workers and to tend to your plants, which cannot detach themselves. Be ready to prune off broken branches as soon as the damage happens, move fences to enlarge or reconfigure protected areas, add mulch or tarps, etc.

Stand up for your plants. You are the expert when it comes to their needs and condition. Do whatever you must to maintain the protection you intended and to continue watering and other essentials during construction.

At this point you should recognize that there is a language barrier between gardeners and builders, and compensate for it. Even simple terms like “soil” have different meanings to both, leading to variable interpretations of acceptable quality and density. A concept such as “root zone” may be incomprehensible to a carpentry crew, or exist in an altered state in their minds so that any conversation that involves the term must be confirmed with diagrams and clarifying questions, just as “load bearing wall” may be Greek to you until it’s drawn out. Although there are individuals fluent in both “gardenerese” and “contractorese,” you should assume until proven wrong that everything you say can and will be misinterpreted.

I’ve been admonished, in preparing this material, to prepare myself for righteous anger from those in construction fields, who may think that in speaking of all a homeowner must do to protect their landscape I am belittling the skills construction workers have and their sense of responsibility. I hope that I’m making it clear that I do respect skilled and responsible construction workers but at the same time I know that my expertise and that of any gardener deserves as much respect. We are expert in our differing disciplines and when we share the same ground, we must communicate carefully. That begins with respect, extends through explanations of technical terms on both sides, and is never hurt by a few shared cold lemonades on a hot day.

After construction ends

Inspect your plants and the soil for damage. Photograph the plants. These images may be invaluable as benchmarks to assess their recovery.

Make your landscape a garden once more. Remove the excess mulch, landscape fabric, protective fencing and tarps. Aerate the soil. Check that sprinklers are working, and make necessary repairs and adjustments. Untie tied-back plants, bring back temporarily relocated plants, and add new plants.

Watch for signs of stress. These signs may not show up right away—in fact, symptoms of stress may not show up for months or a year in larger plants. The bigger the plant, the longer you may have to keep it under watch.

Give stressed plants kid-glove treatment. Watering is the most important thing you can do, but special fertilizing, pruning and patrolling for particular pests that prey on weakened plants of that type may be in order too. Follow the plan that you made for the plant or had made way back in phase one. It all comes together now, when you see your plants resume the growth rates and beauty they possessed before you were possessed by the construction bug.

You can tell when your trees and shrubs recover from construction stress.Monitor and compare the current growth rate to pre-construction or the species’ average growth rate (listed in books such as Manual of Woody Landscape Plants by Michael Dirr).This sugar maple branch grew just three inches in a year, evident in the differing color of new and old wood.The species’average rate is 8 to 12 inches.It’s still recovering and still needs special attention. — You can tell when your trees and shrubs recover from construction stress. Monitor and compare the current growth rate to pre-construction or the species’ average growth rate (listed in books such as *Manual of Woody Landscape Plants* by Michael Dirr). This sugar maple branch grew just three inches in a year, evident in the differing color of new and old wood. The species’average rate is 8 to 12 inches. It’s still recovering and still needs special attention.

Another way to gauge stress and recovery is leaf size and color. If leaves are smaller than normal or discolored, the plant is stressed.This oak leaf is chlorotic—the plant equivalent of anemia. Chlorosis is as often an indication of root damage as it is mineral deficiency. So pamper this oak with aeration, steady watering and special fertilizer until the leaves tell you it is recovered.

Watching for signs of stress after construction

Symptoms may be immediate or delayed:

Wilting or shedding of foliage during or right after construction.
Development of early fall color or leaves dropping early that season or the season following construction.
Reduced leaf size and shoot growth the next season or later.
Twig or branch loss the next season or later. More needles may drop than are produced on an evergreen. The plant may appear thinner,more transparent.
General growth, appearance and pest resistance may be poor, and secondary problems may appear.

Helping the plant recover

From April through November, water deep and slow throughout the plant’s entire root zone whenever the soil a few inches deep is dry and warm.
Check root growth (dig test hole at drip line) and resumption of pre-construction twig growth rate to determine when the plant has fully recovered.
For every inch of trunk diameter, expect a one-year lag before regular growth resumes.

Article by Janet Macunovich and photos by Steven Nikkila, www.gardenatoz.com.

Growing grass under trees

June 18, 2019 • Leave a Comment

Our yard is shaded by oaks. We overseed every year with shady grass mix. But by the next spring most of the grass has died. What can we do to grow grass in this situation?

You have a couple of choices. You can continue the frustrating cycle of growing grass, or take an alternative approach to living with your oaks. Turf grass needs sun to germinate and establish a root system, even if it is the “shady grass mix.” If your oak canopy is heavy and dense, you could have the canopy judiciously thinned by a trained arborist. They will prune when the trees are dormant in winter and there is little chance for them to be infected with the oak wilt disease. This might open up the canopy enough to let the turf lawn get established.

However, you should know that oak trees can take up to 50 gallons or more of water a day. So while you are watering that lawn you’ve overseeded, the oak trees with their extensive root systems are enjoying the feast. The turf grass never gets its root system established because the oaks are not only shading it out, but also absorbing most of the water.

This is not necessarily a bad thing. Oak trees are preferable bastions of shade. The alternative is to try a different groundcover that isn’t lawn. Oak trees create dry shade. It sounds like your lawn is fairly thin underneath them, which is why you keep overseeding every year. Why not plant dry shade-loving perennials? There are a number of low maintenance plants that would not only lend interest to the landscape under the oak trees, but are low profile, will come up every year, will succeed where turf grass fails, and will provide “green coverage” that you don’t even have to mow.

Consider a mass planting of variegated hostas that would “light up” the shady area under the canopy. Another perennial often used where grass is unsuccessful is lily turf (Liriope spicata). It even looks like grass, but has the bonus of a purple-blue flower in summer, which turns to a red-brown berry in fall. At the outer edge or drip line of the canopy, you could mass plant Stella d’Oro daylilies. They tolerate a wide range of soil types and light conditions. Their yellow blooms are continuously cheerful and when finally done blooming, their foliage lasts until frost. A simple ground-hugging vine is vinca, sometimes called myrtle. It produces a lovely blue flower in spring that shows well in heavy shade. There is also the nice spotted dead nettle (Lamium maculatum) with its silver and green mottled leaves. The cultivar ‘White Nancy’ produces a lovely white flower while other varieties produce pink blossoms mid-spring.

So there are several alternatives and choices to groundcovers that aren’t turf grasses. You need to decide where to put your money: into perennials that will succeed in the shade of your mighty oaks, or continue trying to grow turf grass that will always struggle.

Wanted: Sightings of Michigan’s largest trees for the Big Tree Hunt

September 17, 2018 • 2 Comments

Whether you’re out in the woods or wandering through city streetscapes, keep your eyes open—you may spot one of Michigan’s largest trees!

Started by ReLeaf Michigan in 1993, the Big Tree Hunt takes place every two years and helps catalog the state’s biggest trees. Your assignment: Seek out the most majestic trees in your area and report them, because tree-spotters can earn certificates and prizes. “This is a really fun reason to get out and enjoy nature,” said Melinda Jones, executive director of ReLeaf Michigan. “It also helps raise awareness and enjoyment of the trees in our landscape.”

The Big Tree Hunt is one way to discover candidates for the National Register of Big Trees, which so far includes 19 Michigan trees. The biggest tree spotted on the last hunt is a sycamore in Lenawee County with a 315-inch girth.

ReLeaf Michigan is a nonprofit group that encourages planting trees. Entries, either online or hard copy, will be accepted until September 3, 2019. Find out how to participate by visiting www.bigtreehunt.com or calling 800-642-7353.

Ask MG: Why is my Purple smoke tree not smoking?

March 10, 2018 • 7 Comments

I have a purple smoke tree that is about 9 years old. It is a large, healthy tree, but it has never “smoked.” Every spring it is full of blossoms, then when other smoke trees are beginning to smoke, the blossoms on this tree shrivel and die. I have tried watering it more, I have tried watering it less. Any ideas? J.W., Ann Arbor

Although smoke tree or smoke bush (Cotinus coggygria) requires well-drained soil and full sun, it is quite adaptable to different soil conditions. A large shrub or small multi-stemmed tree that can grow to 15 feet tall, it can work as a background plant for the mixed border or as a single specimen plant. Its claim to fame is the cloud of pinkish gray “smoke” that covers the plant in the summer. The effect is the result not of flowers, but of tiny pinkish hairs on the small fruits that occur in large clusters. There are some popular cultivars with purple leaves and darker flower clusters, such as ‘Royal Purple,’ ‘Velvet Cloak,’ and ‘Nordine Red.’

While smoke bush is relatively easy to grow, it can use some help in the early stages of development. For a new plant, avoid planting in waterlogged or poorly draining soil. For an existing plant, dig a dozen holes with a crowbar at the drip line that are a foot deep. Fill these holes with 5-10-10 fertilizer. This should be a one-time application. Early spring is best but it can be any time. It isn’t necessary to repeat this unless the smoke bush is not thriving in later years. Woody plants are going to be happier if you don’t overdo it. Annuals, tropicals and turf are heavy feeders, but over-fertilizing perennials and woody plants can force them to produce more stems and leaves than they want to, which can lead to unnecessary stress. Once established in the landscape, shrubs and trees adjust to the nutrients in the soil and often don’t want too much extra pampering. Avoid fertilizing (directly or indirectly) with high nitrogen (lawn) fertilizer; nitrogen promotes stem and leaf growth at the expense of flower production.

If your tree is planted in the lawn, remove the grass in at least a 6-foot diameter area around your tree. Mulch the area (do not pile mulch up against the trunk) and water infrequently: a good soaking once per week is much better than multiple small waterings. Smoke bush is drought-resistant and overwatering can result in few or no blooms, and makes it more susceptible to disease. Woody plants need watering less frequently than tender annuals, lawn, or herbaceous plants. Most established trees and shrubs can go weeks without supplemental watering except in very hot or windy weather.

Scientists say there are over 60,000 tree species in the world

May 3, 2017 • Leave a Comment

NPR:

Wondering how many kinds of trees there are? There’s now a database that can answer that.

Scientists from the U.K.-based Botanic Gardens Conservation International say they have compiled the first-ever comprehensive list of all known tree species, totaling 60,065 different kinds.

The database includes information about where each species is found geographically. More than half of those species are only found in one country, the researchers wrote in the Journal of Sustainable Forestry. And many of them are threatened with extinction.

Read the full story here…

Website Extra: The Giving Trees

May 3, 2017 • Leave a Comment

Out of tree death has arisen an enchanting garden

Editor’s Note: The following are bonus photos from a profile of Janice Cooley and Paul Stedman’s garden featured in the May 2017 issue of Michigan Gardener. To read the full story, pick up a copy of Michigan Gardener in stores or read it in our digital edition, which can be accessed for free on our home page.