Plant Health Care (PHC) is a term often denoting a service offered by companies in the green industry indicating the company offers a comprehensive program to manage the health, structure and appearance of plants in the landscape. If they don’t offer an aspect of the program, they generally will be able to advise you on what is needed and offer referrals to a company that can supply that need or resources you can look into if the care can be managed by the homeowner.
A component of PHC is Integrated Pest Management (IPM) which is the diagnosis, monitoring and application of the least toxic choice in dealing with plant pests.
Natural and applied methods are considered in IPM. Natural methods are environmental events which will stop the progression of the problem, such as a change in the weather that was conducive for a specific disease. An example being a disease pathogen may thrive in moist, cool conditions; the weather gets hot and dry, the disease progression ceases. If this can be anticipated, it will affect the choice of whether to apply any other method or let nature handle the situation.
Applied methods are ones we have to implement. They include cultural, biological, mechanical controls with chemical control being used as a last resort.
We can’t eradicate all pathogens or pests from the environment. It isn’t practical nor is it desirable. IPM recognizes the need for a certain number of “prey” insects the “predatory” insects will feed on. Many diseases are endemic to an area and only become problematic given the suitable environment and the host species.
Whether the problem is insects or a disease, it is crucial to correct any cultural practice that may be contributing to the problem. Without doing so, it is pointless to apply any pesticides. Therefore, cultural controls are a first step in PHC/IPM programs.
If available, plant resistant species for diseases known to be prevalent in your area. A classic example is dealing with fireblight, a bacterial disease potentially devastating to members of Rosaceae. Numerous cultivars of Malus spp, apples and crabapples, have been developed for resistance to fireblight as well as apple scab, powdery mildew and rust diseases. Combining best management practices and planting resistant trees may significantly reduce or even eliminate the need for chemical application.
Landscape management practices may inadvertently contribute to establishing a suitable environment for diseases or creating a succulent smorgasbord for insects. An all-too-common example includes over-fertilization. Many articles, websites and well-meaning professionals advise the application of nitrogen as well as other plant nutrients in quantities exceeding plant need.
Excess nitrogen pushes vegetative growth at the expense of root development, storage and defense. This succulent vegetation is highly attractive to many destructive insects and nitrogen virtually feeds many pathogens causing diseases to be more virulent and prevalent. Examples include Armillaria root rot, fireblight, fusarium, phytophthora, powdery mildew, pseudomonas and rust diseases.
Weed and feed products commonly sold for lawn care maintenance have herbicides in them that are designed to manage broad leaf weeds. Trees, shrubs and many flowers are broad leaf species and are susceptible to these herbicides as well. If weed control is desired in turf grass, it is far better to discretely spot treat if populations are beyond controlling by hand.
Another cultural practice that influences the suitable environment is inappropriate watering. Too much and you will be suffocating roots creating a suitable environment for root rot diseases. Too little and you will weaken tree defenses making the plant more susceptible to opportunistic pathogens on weakened tissue as well as attracting some of the most damaging insects, the borers, who are drawn to drought-stressed trees.
Mowing and weed eating are often maintenance practices which cause physical damage to trees leaving wounds that become infection courts for both pathogens and insects. (See my blog Can A Weed Eater Really Kill A Tree?) Creating a protection zone (no-mow zone) around the trees, at least in a minimal mulched area if not a full tree island, will eliminate these man-caused injuries. (See my blog Benefits of a Tree Island)
These are a few examples of cultural practices which should be evaluated and altered as needed.
Nature has provided many organisms which combat diseases and insects. In a balanced, natural setting these may be sufficient to keep damaging agents at an acceptable level. However, in our built environment, they may not be able to keep up with the task. It may be desirable to release biological organisms when they are not in sufficient numbers. Examples of these would be some of the bacteria, e.g.., Bacillus subtilis, that combat diseases such as fusarium and phytophthora or bacteria, e.g., Bacillus thuringiensis, that control numerous insect species.
Biological control may also include the release of predatory insects to control pests, such as lady beetles and green lacewings which are both voracious eaters of aphids. A side note: if purchasing these beneficial insects, lady beetles will be more effective in a closed environment such as a greenhouse unless there is sufficient food and water immediately available. Green lacewings may be a better choice in an open-air landscape.
Mechanical or physical controls
Physical manipulation or creating an obstruction to protect plants can be very simple and effective. Examples would be fencing your tree to keep deer from browsing and rubbing or protecting the trunk of a tree to keep the neighborhood cat from using it as a scratching post.
Chemical pesticides are kept as a last resort rather than a first so we have a place to take a final stand. With that said, there are some pests that have been identified as requiring the hammer approach first and last, just not nearly as often as some think. There is also a vast array of chemical pesticides to use including low toxic, organic, inorganic and synthetic products. Wading through the plethora of products is daunting and confusing. Trying to make sense of the labels can be just as daunting and confusing. It is strongly urged to consult a professional applicator prior to applying any pesticide yourself.
Broad spectrum cover sprays, sprayed over the entire property (plant population), will inevitably harm or reduce the number of naturally occurring beneficial and predatory organisms. These are the ones that can keep injurious pests under control and should be protected as much as possible.
Many pests are not damaging to long term plant health. Many pests are a nuisance to us more than they are a problem to the plants. And some need an aggressive approach. A good PHC technician should be able to help you wade through the potentials and come up with a game plan that will address the issues, causing as little negative impact to as many beneficial organisms in the environment as possible.
Biotic refers to “living” as opposed to non-living which is referred to as abiotic. Biotic diseases are pathogenic, infectious and can spread from plant-to-plant, generally of the same species. They are caused by organisms such as fungi, bacteria, viruses, nematodes and mycoplasma-like organisms (MLOs). (Please don’t ask me to explain MLOs.) Fungal diseases are the most common but Iwant to stress that not all fungi cause diseases. Most organisms are necessary and vital constituents in our environment.
When clients call about a problem with their trees or other plants, they often do not know whether it is an insect or disease issue and many times do not consider abiotic issues at all. However, many diseases actually stem from abiotic disorders as pathogens take advantage of a weakened or damaged plant.
Diseases require three circumstances in order to develop: 1) A pathogen has to be present, 2) a susceptible host has to be available and 3) the suitable environment has to exist. If any one of those criteria is not present, the disease will not develop. This is called the disease triangle.
Many organisms exist in a non-pathogenic state performing necessary functions in the environment, only becoming pathogenic when a susceptible host and suitable environment coincide. Trying to manage diseases by eradicating the pathogen is seldom (if ever) feasible or even desirable. Instead, reduce the potential of a susceptible host or disrupt the suitable environment.
A plant with susceptibility to a disease becomes the host when the pathogen and suitable environment are present. A number of plants have been specifically developed to resist common diseases. Determine what are common and damaging diseases in your area and search out resistant cultivars of plants.
An example would be many apple and crabapple trees are susceptible to four primary diseases: fire blight, apple scab, powdery mildew and rust diseases. There have been many cultivars of these popular plants developed with varying degrees of resistance to one or all of these common diseases. Instead of fighting a likely problem, minimize the potential by selecting one of these resistant cultivars.
A suitable environment is when the temperature and moisture are conducive for disease development. And it varies from disease-to-disease. We are somewhat at the mercy of Mother Nature here. Cool, wet springs are going to be very suitable for certain diseases such as anthracnose.
Many diseases are spread by wind and/or rain. However, when you consider that water, not just in the form of rain, but irrigation practices as well, can create a suitable environment, then managing irrigation practices may go a long way to minimizing the potential for diseases being able to dock.
Knowing a disease’s life cycle may give a clue as to whether you should overhead water or not. Some diseases are dispersed by rain or splashing water and, therefore, you would want to avoid overhead sprinklers. However, some, for example powdery mildew, do not dock on wet surfaces. In that case, overhead watering susceptible plants, such as bee balm, Monarda spp, and crabapple trees, Malus spp, may be a good idea. (Note: there are actually a tremendous number of plants susceptible to powdery mildew). You need to know when the appropriate time of day to overhead water….and that may vary area to area. Here in Western Montana, I have been successful at controlling powdery mildew by overhead watering in the early afternoon. This timing may not work for you. Note: if a plant susceptible to powdery mildew is surrounded by plants susceptible to other fungal diseases that are enhanced by overhead watering, well, you have to pick your battles.
Some fungal pathogens thrive in a crowded environment which blocks air flow. Judicious pruning that opens up the canopy may reduce the likelihood of the pathogen developing.
Pruning out diseased portions of a plant is often very effective at controlling certain diseases. It is recommended to dispose of the debris off site. It is also often recommended to prune fungal or bacterial diseased tissue from a plant during a dry period.
Determining the most likely pathogens in your area, the environmental conditions under which they thrive and their life cycle combined with an inventory of your species listing their individual susceptibilities will go a long way in helping you devise a plan allowing you to minimize potential problems. Nipping the problem in the bud….so to speak.
Abiotic refers to “non-living” as opposed to biotic (living). An abiotic disorder is a plant malfunction caused by non-living, environmental or human-made agents. Yes, humans are living but generally the implements they wield which harm trees are not: e.g., lawn mowers, weed eaters, vehicles, herbicides. Another criterion that defines abiotic is they are not infectious. Animal damage is listed under abiotic as the damage they cause is not pathogenic or infectious. (I know, life gets confusing.)
When clients call about a problem with their trees or other plants, they often do not consider abiotic possibilities, rather assuming the problem stems from insects or disease. The reality is the vast majority of time, the problem is abiotic in nature or stemmed from an abiotic injury.
Environmental extremes are beyond our control: e.g., lightning, heavy snow and wind. Damage caused by these agents should be assessed for prognosis of safety and survival and a management plan devised. Is the damage significant? Can it be rectified? Will the tree survive? Does it pose a safety issue due to proximity to infrastructure or human proximity?
Activities which cause abiotic injuries we can influence involve common practices in managing our landscapes.
Lawn mowers and weed eaters can be deadly weapons to trees. My blog, Can My Weed Eater Really Kill a Tree, goes in to this implement in detail. Lawn mower damage from constantly striking the tree trunk close to the ground is also a common agent of creating an infection court allowing diseases to gang a toehold but can result in progressive decline even without a disease. It is easy to discount incidental contact with a tree, thinking “it can’t be that bad”. But it can and it is.
Another lawn care practice potentially damaging to trees that many don’t consider is the application of herbicides in controlling broadleaf weeds.
Many fertilizer products are listed as “weed and feed”, meaning they contain an herbicide in them as well as a fertilizer. This is supposed to address those pesky dandelions and other weeds in lawns. However, trees, shrubs and many perennials and annuals are broadleaf species as well. And in the case of trees and shrubs, their root systems may be occupying the same soil space as the lawn. What is applied to one affects the other. This is why we recommend creating tree islands or mulched areas around trees. (See my blog, The Benefits of a Tree Island)
Tying strings, garden hoses, installing swings or laundry lines by wrapping chains or line around limbs are another practice that may cause serious injury to a tree.
This includes staking for stability after planting and the tags that come with the tree from the nursery. Limbs grow, but strings, lines, ropes and chains don’t. The tree grows around them often resulting in constricting the vascular system of the branch, stem or trunk.
And then we have irrigation practices. It is easy to get into a rhythm of watering without really checking to see if the plants are being appropriately watered. Consequently, it is all too common to see over- or under-watered plants. One size does not fit all. And, yes I am going to say it again, trees grow. As they get bigger, their water requirements increase. Not only that, but if you have a sprinkler system that was set up when they were first planted, the system needs to be moved away from the trunk.
The roots are far away from the trunk and that is where the water needs to be applied. That growing trunk and buttress roots can also pinch off the water lines entirely.
Trees should be protected from animal damage before it happens. Waiting until you see the damage is too late. Some trees will stay vulnerable to animal damage their entire life and you need to make the decision whether you want to deal with that kind of commitment or pick a tougher species.
Planting herbaceous barriers to discourage browsing from larger animals may work but can backfire as they provide protection for rodents from natural predators.
There are many products to discourage browsing by deer. I have had good luck with liquid products as well as hanging bits of Irish Spring soap from target trees. You may need to experiment to see what will be effective in your area. However, if you are in a particularly heavy use area, fencing might be your only reliable recourse. You can be as creative and decorative as you wish, or keep it simple but effective, combining form and function. Works very well.
The answer to this frequently asked question, as with most questions pertaining to arboriculture, begins with the phrase “It depends…”
The short answer would be “If they need it.” Then a follow up question, of course, is “How do I know if they need it?”.
If you live in an area where the ground does not freeze and you have not had any precipitation, then your trees may very well need a drink or two in the winter.
If you are in an area where the ground does not freeze and you are getting regular moisture, then you probably do not need to water your trees.
If you are in an area where the soil DOES freeze and you are not getting any precipitation...well, if the ground is frozen it will do no good to create an ice rink around your tree.
If you are in an area where the soil freezes and you have snow on the ground, you don’t need to water.
If you are in an area where the soil freezes but you have periodic thaws, if you have snow on the ground you do not need to water…the melting snow will take care of it.
If you are in an area where the soil freezes and you have periodic thaws but no snow on the ground then check the melted soil….is it muddy? You don’t need to water. Is it dry? You do need to water.
© 2018 McNeill’s Tree Service
The decision to select native plants versus non-native plants is a personal one. There is no one right answer. There are appropriate species within each category and inappropriate ones as well.
There is a misconception that all native plants are more drought tolerant than introduced or non-native plants. That depends on the species. It is a statement you cannot take across the board. There will be exceptions in both directions.
Plants need water. Different species require different amounts of water. Some can go for longer periods of time without water than others. But a general premise is: trees grow where there is adequate water for their needs. Here in the Bitterroot Valley of Western Montana, native trees will be found along creek and river beds or in the mountains along drainages where water is more plentiful. The native plants surviving further from water sources are drought-tolerant species such as juniper, Juniperus scopulorum, sagebrush, Artemisia spp, rabbitbrush, Ericameria spp, as well as various grasses and forbs of high plains semi-arid environments. An unfortunate reality is many of our native species are not necessarily suitable for a managed landscape.
People living in areas with abundant rainfall and moderate climates have a plant palette consisting of a large selection of native species. This may enable the homeowner or landscape designer to stay within the native range and still create an interesting and diverse landscape. Those living in dryer and/or colder zones with limited species are going to have a harder time.
Here is, in my opinion, the caveat few take into consideration: there is arguably no species native to the built environment. Once we move into an area and alter the surroundings with hardscape, compacting the soil, bringing in fill from other areas, changing topography, the plants originally “native” to that site are no longer. Or probably a better way of saying it is the site is no longer suitable for that native species.
Then there are people with a flexible definition of “native”. For example, some broaden the limitations from their state to include any species native to North America. To my mind, if they are willing to use an introduced species from across the continent, Canada and Mexico (and then if you want to use the United Nations designation, add the Caribbean as well), why limit yourself?
Trading and exchanging seeds and plants has a very, very long history going back thousands of years. As global trade escalates, so do the pluses and minuses from those transactions. There are many beautiful, exciting plants to enjoy in our landscapes. And, yes, many we should be cautious of. However, non-native is not synonymous with invasive. That is another topic entirely.
Photosynthesis is the process whereby plants fix carbon dioxide (CO2) from the atmosphere, combined with water molecules (H2O), they utilize light energy (the sun) and convert it to chemical energy to produce organic compounds (C6H12O6) releasing oxygen (O2) into the atmosphere. Most references simply call the organic compounds sugar and, yes, the formula is a broad formula for glucose. However, I believe just saying “sugar” leads people to picture a sack of refined sugar you buy in the store. Plants do not produce highly refined, white sugar. But I digress.
Most descriptions of photosynthesis stop there emphasizing the benefits plants give us by releasing O2. After all, that is what we need to breathe. Maybe you are wondering what else can be said.
The thing is, the cycle doesn’t stop there. Please read on.
Recap: Plants fix CO2, combined with H2O they utilize light energy and convert it to chemical energy to produce organic compounds and O2. Now, here we go…
Plants utilize the organic compounds in structural growth, store some for future resources and use them for other regulatory processes. It (the plant) also exudes a portion of these organic compounds through the roots into the soil to be utilized by soil organisms for energy and food.
Organic matter (OM) builds in the soil as plants and soil organisms die. Microbes process the OM releasing plant available nutrients as they do so. As soil organisms die, more plant available nutrients are released. While all this digesting and processing is taking place, plants and organisms respire. Respiration is essentially the opposite of photosynthesis in that they utilize oxygen and exude carbon dioxide into the soil for release back into the atmosphere where it is taken up by plants once again.
This cycle is part of the soil’s self-regenerative capability and is, in fact, mandatory to all life on Earth.
Reality check: We need plants, but they do NOT need us! They created the atmosphere that enables us to exist. They are in essence environment builders.
August 7, 2018, I had the great pleasure and privilege to speak at our International Society of Arboriculture annual conference. This year it was held in Columbus (affectionately called CBus), Ohio. The Greater Ohio Convention Center was familiar to me as the TCI EXPO 2017 (Tree Care Industry) was also held there.
The presentation I gave was Creating Healthy Soil in Residential Settings in which I introduce characteristics of healthy soil, how healthy soil is created and how we can enhance those qualities in our landscapes. This topic is near and dear to me as I have felt too many succumb to artificial and synthetic management of our residential soils to the detriment of the soil organisms and sustainability of the natural ecosystem. This talk has been well received, which thrills me. After all, you never know if there are kindred spirits out there. But there are. Many arborists and homeowners are very interested in learning how to promote and enhance the natural ecosystem.
Using my own property as a case study, I point out how you can go from a “barren” landscape to a vibrant, species-diverse one without synthetic fertilizers by “simply” enhancing the habitat. Key components are adding organic matter, getting living roots into the soil, and watering appropriately.
Most of our property is left natural but we enhanced the area close to the residence to give us our oasis of greenery while also producing a mecca for birds and wildlife. Although, I finally said enough to the deer deprivation and my husband built the 6 foot fence. In one season the volunteer growth, of which I have referred to in another blog, has blossomed, so to speak.
My message? Enhance the habitat and let the organisms in the soil do their job.
June 29, 2018, saw me in Encinitas, California, for a Plant Health Care (PHC) workshop co-presenting with Mike Raupp, Ph.D., an entomologist from the University of Maryland. These “roadshows” are put on by the Tree Care Industry Association (TCIA), our national arborist association, and sponsored by various companies. In this instance, the sponsor was Rainbow Treecare Scientific Advancements out of Texas.
Attendees were introduced to methods and best management practices in plant health care and integrated pest management (IPM) from monitoring for insect and disease issues, diagnosing, and prescribing treatment to learning characteristics of healthy soil. There were classroom lectures by both Mike and I, a presentation and demonstration of their equipment from Rainbow Treecare Scientific Advancements representatives and a hands-on walk through the botanic gardens identifying insects and disease issues as well as how best to manage them.
We had a diverse group of participants from experienced professionals to “newcomers” to PHC wanting to know how to incorporate a pro-active service into their company’s structure. Everyone stayed attentive and focused to the last. Which is really saying something because it was an intense 8 hours with short breaks and a quick lunch.
For me, well, it was a wonderful experience. I love talking to people about trees and soils. Everywhere I have spoken I have been met by people who are seriously interested in learning more. And I find I always learn something from them as well. You simply can’t know enough and talking with people in different climates, zones and regions exposes you to situations you just don’t meet “at home”. And yet, you also find a common bond or theme. I have yet to meet with an arborist and not had something in common to talk about.
Looking forward to the next Roadshow in Cleveland, OH, August 9, 2018, at Cleveland Botanic Garden Woodland. If you are interested, the Upcoming Events page on this website has the registration link.
Ok, I bet you think this post will be about the human volunteers that come in so handy at many events. Au contraire. Let’s talk about that other biological volunteer, the plant that pops up where you didn’t plant it.
Volunteers come in many shapes and sizes and, yes, in a range of desirability as well. We have the volunteers that propagate and spread from plants on our own property, readily identified. There are those that show up from unknown origins but suspected transport is often birds. These may be native or non-native. And then there are, shudder/groan, those dreaded, unwelcome visitors that appear as bad actors on our individual State’s “Noxious or Invasive Weed List”.
Dealing with the Noxious or Invasive Weeds first, these we really don’t have a choice in options. Many states have a list of weeds that are mandated to be controlled. They are not welcome, they have proven to be invasive to the detriment of an existing plant or ecosystem and, sometimes, there is a zero tolerance with fines involved. I emphasize the need to pay attention to your individual State’s list because not all plants are invasive or noxious in all areas. A rather classic example of this is the Norway maple, Acer platanoides. This popular shade tree has been listed as “invasive, not banned” in Connecticut and “prohibited” in Massachusetts according to the USDA NRCS Plants Database. https://plants.usda.gov/core/profile?symbol=ACPL This site also has a list of federal and state lists for noxious weeds. But to tell you the truth, looking at some of the dates, I would google your state to be sure you get an up-to-date list. For instance, the USDA website has a list dated 2006 for Montana, but a quick google to mt.gov shows a current list dated February of 2017.
Many of these plants were introduced in the past as ornamentals or had the ability to thrive and grow quickly in harsh environments. They have since “escaped” captivity and has no trouble reproducing and surviving all by themselves. Unfortunately, in the case of those declared “invasive”, that ability proved to have negative results in its new home.
Some plants have “naturalized” and are not listed as noxious weeds. The white-leaf poplar, Populus alba, is an example. They make a good field tree where a grove is desirable. They do not make a good landscape plant where above ground space is limited and where there is a managed lawn.
Back to the more acceptable volunteers. At our place, we have a basic philosophical approach: unless it is identifiable as a listed noxious/invasive weed, it can stay until we determine (1) what it is, (2) if we like it and (3) if where it has set up camp is acceptable.
Interpretation of the criteria can produce lively discussions between my husband and I on defining “liking” and “acceptability of site”. He has a tendency to look far into the future as to whether or not the new addition to the property will be appropriate. I am much more inclined to take the “wait-and-see” approach since not all survive anyway.
Example: A box elder, Acer negundo, has volunteered in a garden spot in close proximity to an existing honeylocust, Gleditsia triachanthos. He keeps telling me there is no way a tree of that potential size will work there. MY contention is that I don’t think it is going to survive long term and I want to see how long it does survive. (Pretty sure a seed came in from a job we did in the past as this is in an area mulched with whole tree chips.)
I do like to leave plants until I have identified them. One volunteer my husband wanted me to pull has turned out to be a clove currant, Ribes aureum. Again, he keeps saying it won’t work long term where it is. Ok, it is a shrub with the capacity to get 8 ft by 8 ft and planted itself right next to (another) volunteer (who got there first), an elderberry (of as yet to be determined species) which also gets rather large. Both are fairly close to our house and close to ANOTHER volunteer, an oak-leaf mountain ash, Sorbus hybrida, a cross between the European mountain ash and the Swedish mountain ash, which is a tree with the capability of getting 30 ft tall and 20 ft wide. I just keep telling him this will give him ample opportunity to say “I TOLD you so!” in the future.
The clove currant has a lovely flower with the most gorgeous clove scent. The pollinators have already voted it the Best Newcomer this year. The elderberry had berries its first year (2017), which were a big hit with the birds. The mountain ash was a ladybeetle nursery last year in its first appearance hosting over 14 larvae. Transplanting is an option but I don’t want to chance losing any of these. After all, we can always move the deck.
This could be my shortest post ever: Yes! Generically called weed eaters, weed wackers, trimmer/edgers, these are the gas, battery or plug-in electric tools used to cut down weeds or grass next to trees, buildings, fence lines or to create an edge along a sidewalk or driveway.
Innocuously called string trimmer line, many people don’t realize the damage caused by the fast spinning, plastic line. After all, trees have protective bark. But depending on the species that bark is not always very thick. The repetitive injuries, often on a weekly basis during the growing season, can eat into even the thicker bark of trees. And you cannot help but hit the tree if the grass or weeds are growing up right against the trunk. You may not see the damage but it is happening.
Weed eaters aren’t the only culprits in the lawn care line up that cause damage to trees. Let’s take a look at other lawn care practices.
The lawn mower
To the person mowing the lawn, the tree is an object specifically planted to, at the least, be an annoying object to avoid and, at worst, be actively out to create grievous bodily harm. I don’t know if the physical act of running the mower into the tree, on purpose mind you, is some kind of subliminal payback but it is strongly not recommended due to the damage it can cause the tree.
A case in point: We were called out to remove a tree with severe dieback on one side of the tree. The people asked if we had any idea what caused the decline. After looking at the base of the tree, we asked about lawn care practices. Checking the base cut after the tree had been taken down, there was a distinct time of injury with limited growth. I counted growth rings on the live portion to see when the injury first appeared. When I told the homeowner, it looked like the damage had started approximately 12+ years ago, he stated that was about when he got his riding lawn mower and the flange from the mower always hit the tree on that side when he mowed.
In addition, some tree species have shallow root systems, staying close to the surface. This can be exacerbated by a watering regimen that applies a little bit of water frequently rather than the preferred longer sets less often. These roots will inevitably be clipped by the lawn mower creating an open wound on the tree root for pathogen entry and annoying the heck out of the lawn care provider. This issue can be avoided by better plant selection and better watering protocol.
Many people like to control broadleaf weeds in their lawns. And I understand that. However, many trees, and shrubs for that matter, are broadleaf species. Just because they are bigger than dandelions does not mean they are not susceptible to the herbicides applied to control annoying weeds. Many of these products are available to homeowners as well as professionals. And as such, I believe people tend to think if it is “over-the-counter”, it can’t be too lethal. In fact, some products can kill trees, susceptibility varying depending on the species. Unfortunately, please do not assume a professional pesticide applicator is fully aware of the potential for damaging trees and shrubs on your property. We see chronic damage to many shrubs and trees by both the homeowner and the professional.
Damage can be subtle and potentially lethal or dramatic and definitively lethal.
With any of these factors, you may think it doesn’t matter because the tree didn’t die and, in fact recovered with no visible signs of lasting damage. However, stress has been applied and this is often a recurring event. Stress builds up in a tree. It doesn’t “go away”. A stressed tree is more susceptible to other issues such as insect deprivation or pathogens. We try to avoid creating unnecessary stress whenever we can.