|Yard & Garden Line News
Volume 7 Number 11 July 15, 2005
Knowing When to Hire an Arborist
Patrick Weicherding, Regional Extension Educator, Natural Resources and Environment
Tree experts, known as arborists, provide a variety of services to help you protect the valuable investment you have made in your trees. Proper tree care is part of that investment and it can lead to substantial returns. Well cared for trees are not only attractive but will also add real value to your property, while poorly maintained trees end up being a liability with high costs for take down and removal. Knowing why and how to hire an arborist is pretty straightforward; knowing when to hire an arborist is not always so easy. Since this is an important decision for most property owners some specific guidelines on knowing when to hire an arborist might be useful. But first, let's briefly review the "why" and "how" of hiring an arborist.
Linnaeus may have
planted this tree
Why hire an arborist?
The simple answer to this question is that most arborists are more knowledgeable about trees, tree biology, and tree care and are better equipped to provide proper care than the average property owner. An arborist by definition is "an individual who is trained in the art and science of planting, caring for, and maintaining individual trees." Much of the training is acquired through education and certification but a lot of it comes from years of professional experience. A well-informed homeowner can provide proper tree care (planting, watering, corrective pruning, mulching, etc.) to young trees in the landscape but trees grow quickly in size and most homeowners do not have the training, experience or equipment to work safely on large trees.
How to hire an arborist?
Hiring an arborist is easy. Just pick up the yellow pages of your phone directory and look under "Tree Service." You'll find hundreds of companies listed offering a wide variety of services. Call the first one on the list or the one with the biggest and most attractive ad or, better yet, close your eyes and point to one at random to call. After all, if they're listed in the yellow pages they must be reputable. This tongue-in-cheek advice may be the easiest way to hire an arborist but it may not be the best way to select a reputable one. When searching for an arborist or tree care company, there are several things to look for before making a selection:
¤Certification - Ask if the arborists on staff are certified by the International Society of Arboriculture (ISA). ISA offers a range of certification credentials from certified tree worker to certified arborist. To be certified, individuals must pass a voluntary comprehensive exam. Certification must be maintained through continuing education, which means they should be up to date on the latest in arboricultural technology and are knowledgeable of acceptable tree care practices.
¤Some municipalities also require licensing for tree care companies. The purpose of licensing is to restrict entry and control an activity or a profession, presumably to only those qualified. Possession of a license, however, doesn't ensure quality tree work. It simply means that the tree care company has the privilege to operate within the municipal limits because they paid the required license fee.
¤Professional affiliation - Ask about membership in professional organizations such as the International Society of Arboriculture (ISA), the National Arborists Association (NAA), or the American Society of Consulting Arborists (ASCA). Affiliation with these organizations demonstrates a willingness to keep current on the latest techniques and information.
¤Advertisement - When checking the yellow pages of your local phone directory look for arborists who list themselves as ISA Certified Arborists or display the official logos of their professional memberships. Also look for logos of business accreditation such as the Tree Care Industry Association (TCIA), which requires they have an ISA Certified Arborist on staff.
¤Most reputable tree care professionals do not go door-to-door soliciting business, so avoid those companies that show up at your doorstep offering to prune your trees.
¤Insurance - Ask for proof of insurance and then verify coverage with the insurance company. A reputable arborist should have insurance to cover personal and property damage as well as worker's compensation. If you hire an uninsured tree worker, you can be held liable for any damages or injuries that occur while they are on the job.
¤References - Ask for references from past customers and do not hesitate to check them, or to visit the locations where the company or individual has done tree care work.
¤Estimates - Do not be afraid to ask for an estimate, and it's best to get more than one estimate. Keep in mind, selecting the lowest bid is not the best way to select a tree care company. Rather, when examining the bids, look at all specifications and credentials, and the work to be done to determine which company will provide the best service with the skill and professionalism needed to protect your investment. And, most importantly get it in writing. Most reputable arborists will have the customer sign a contract so be sure to review it and do not be afraid to ask questions before signing.
¤Responsible practices - Reputable arborists will only perform industry-accepted practices. Unacceptable practices include tree topping, using climbing spikes on trees that are not being removed and removing or pruning trees without a good reason.
Remember: at first glance a well pruned tree often looks as if no work was done at all.
When do I need an arborist?
One of the best ways to help you answer this question is to educate yourself on some of the basic principles of tree care. Such information is available from the Forest Resources Extension home page at http://fr.cfans.umn.edu/extension/; ISA's "Trees Are Good" web site at http://www.treesaregood.com/; or the Minnesota DNR's "Minnesota Trees" web site at http://www.mntrees.org.
If you're still out on a limb on this one, review the following questions. If the answer is yes to any of them you need to hire an arborist.
Has a storm damaged your tree?
If you need a chainsaw and a ladder to treat storm-damaged trees, if there are any downed and potentially energized power lines in the vicinity of the damaged tree, or if you are wondering if the tree is worth saving, you need an arborist. In any situation where there is potential for personal or property damage it is very important to immediately call your city forestry department or a reputable tree care company to remove the potential danger. Beware of door-knockers following storm damage. They are often non-professionals who see a chance to earn quick money.
Are there cracks in the trunk, branches or roots?
Cracks form when the load exceeds the capacity of the stem to withstand the load. The vast majority of cracks are caused by improper closure of wounds, by the splitting of weak branch unions, or by flush-cut pruning. Cracks can occur in branches, stems, or roots. Several types of cracks can be found in trees and, like other defects, the severity of cracks ranges across a spectrum. Cracks put a tree at risk when they compromise the structure of the tree by splitting the stem in two or when another defect, such as internal decay and a crack do not provide enough sound wood in the outer shell to support the tree. The presence of multiple cracks and decay indicates a very defective tree. You need an arborist.
Are there mushrooms, conks, or bracket fungi growing on the branches, stems or roots?
Fruiting bodies of fungi are advanced indicators of decay by sap rot and heart rot fungi. Heart rot fungi decompose both the heartwood and sapwood portions of the living stem and sap rot fungi decompose dead branches and dead portions of the stem. Decay can occur in branches, stems and/or roots. Decay results in less structural strength and reduced stability in the tree. If you notice fungal fruiting bodies on your tree and they are accompanied by other indicators of decay like rotten wood, cavities, holes, open cracks or bulges in the wood, you need an arborist.
Does the tree have dead branches or a dead top?
Living trees most often fail at their first defects. Dead trees, however, can fracture anywhere: at the ground line, just above the stump, just below the lowest branch, or anywhere in the crown. Dead tops or branches are symptoms of tree decline. They may remain attached to live trees for several years or may fall off suddenly. They pose a high risk of failure and as time passes, the probability of failure increases. If your tree has dead branches or a dead top and you suspect that your tree is declining, you need an arborist.
Has there been any soil disturbance or construction activity in or near the root zone?
When a tree has extensive root damage, the whole tree usually tips over and falls to the ground because the roots can no longer provide adequate anchoring. Roots can be lost due to excavation, trenching, soil compaction, grading, paving, fungal decay, or environmental stress. Common symptoms of root problems include: decline or dieback in the crown, dead roots, missing roots, broken roots, decayed roots, leaning trees, and presence of fungal fruiting bodies at the root collar. If you notice any of these symptoms, you need an arborist.
Do you plan to build on a lot with trees, and you want to save some of them?
If you plan to build on a lot with trees and you want to save some of them you'll need to develop a landscape protection plan. Careful planning will save you time and money and help to avoid the expense or heartache of later repairing or removing trees damaged by construction activity. In most cases an arborist can be a good addition to your planning team. An arborist will inventory trees on the site, select the trees to be saved, and provide advice on the best way to protect the trees you plan to save. If you don't feel comfortable doing this on your own or if you feel uneasy about the building contractor's tree knowledge, you need an arborist.
Are the leaves on your tree wilting, necrotic, chlorite, malformed or does the tree exhibit early fall coloration and premature senescence and defoliation?
Trees can be injured by biotic and abiotic agents. Abiotic or nonliving agents include environmental, physiological, and other nonbiological factors. Biotic agents are living organisms such as insects, pathogens, nematodes, parasitic plants, and viruses. Whether the cause is biotic, abiotic, or both, an accurate diagnosis is almost always needed to treat the problem. If your tree exhibits any of these symptoms and you haven't got a clue about what might be wrong, you need an arborist.
Are more than the usual number of insects noticeable, or do you see symptoms and signs of their presence?
Insects can cause damage to trees in the landscape. They can defoliate branches, mine or stipple leaves, create galls, bore into the bark and wood, and feed on roots and shoots. Most insects are secondary invaders attacking only weakened or stressed trees. Others are primary invaders attacking healthy trees. If you can't identify the insect that is causing the problem or don't know how to control it, you need an arborist.
Does your tree need to be pruned?
Trees are pruned for many reasons, primarily for safety, health and appearance. Pruning is an art and a science. Knowing when and how to prune to achieve the desired results requires technical knowledge and experience. If you lack experience with proper pruning techniques, lack the right tools, are afraid of heights or if you are not in physical condition for hard work, you need an arborist.
Do you need other services performed on your trees?
Arborists do more than just prune trees or repair storm damage. Most arborists offer a wide range of services including installation of lightning protection systems, cabling of forked trunks or branches, appraising tree value, fertilizing and on-site inspections to monitor tree health. If you think you need any of these services, you need an arborist.
Most arborists are practitioners of Plant Health Care. In other words, they believe in preventative care designed to maintain tree health and vigor. Their Plant Health Care package may provide inspections of your trees for a flat annual fee. This is an excellent way to monitor insect and disease problems in time to take effective action. It can also assure proper early pruning to prevent major, corrective pruning later. Regular maintenance practices will also help your trees remain healthy. To find a certified arborist in your area, visit the International Society of Arboriculture or call 217-355-9411.
Janna Beckerman, Extension Plant Pathologist
Have you checked your ornamental grasses lately? Who knows, they might "got" ergot! Ergot, caused by the fungus Claviceps purpurea, is a fairly notorious fungus to rye farmers, and is beginning to appear in area gardens, on everything from Calamogrostis, to Lyme grass, the little weedy foxtail grass (Agrostis spp), and annual rye planted to stabilize and cover local highways.
Calamagrostis with ergot.
The unintentional consumption of ergot has resulted in colorful history. Ergot, and ergotism (the disease that people and animals suffer from eating the fungus) lands in written human history around the Middle Ages as ignis sacer (sacred fire). The plague of Holy Fire, also called St. Anthony's fire, resulted in gangrenous ergotism. In addition to gangrene, victims of ergot may suffer from paranoia and hallucinations, muscle spasms, cardiovascular trouble, and stillbirths. In the 1500s and 1600s, the symptoms of ergot were blamed on witches -- across Europe, and eventually in Massachusetts. In places where people didn't eat rye, witch hunts were rarities. The amines and the alkaloids in ergot are known for vasoconstriction and psychoactive effects, and some of ergot toxins are very similar structurally to lysergic acid (LSD). Numerous compounds have been isolated and modified for medicinal uses, including uses for treatment of migraine headaches (Ergotamines like Bellamine, Cafergot, Ergosta), post-partum bleeding (Methylergonovine and ergonovine), and various psychological disorders.
Cogito Ergot Sum?
Ergot is readily identified by the dark purple to black sclerotia (ergot bodies) found replacing the grain in the heads of grasses. The ergot bodies are fungus balls that consist thousands of strands of the fungus. Interestingly, the size of ergot is relatively proportional to the size of the seedhead of the infected grass.
Infected Lyme grass.
Ergot overwinters as the hard sclerotia, and germinates in the spring to produce a cup-like structure that releases spores. The spores are blown onto the open flowers, where they germinate. The fungus then infects the embryo of the developing seed, and begins to produce "honeydew," a sticky, yellow, sugary ooze of that contains fungal spores, and attracts insects to spread it to other flowers. As the fungus establishes itself, it grows throughout the embryos and replaces them, eventually producing the dark sclerotia. The long, cool spring resulted in a longer flowering period for many grasses, and has resulted in considerable ergot.
Ergot is more an interesting curiosity in the garden, as opposed to a serious disease problem. It does need to be stressed that ergot is toxic to animals and people. The gardener who has small children or animals that may eat the sclerotia are advised to simply pick the sclerotia out of the seed heads and remove them, or just remove the seed heads completely.
Ergotism and History:
Ergotisms: The Satan loosed in Salem
Springtails In and Around Homes
Jeffrey Hahn, Assist. Extension Entomologist
Many people have recently noticed very small (1/16th - 1/8th inch long), insects inside homes as well as outdoors in the landscape. These insects are wingless and can't fly but they can jump. If you see insects like that you have found springtails. Unlike grasshoppers, crickets, and similar insects that use large back legs for jumping, a springtail uses a forked appendage called a furcula (located underneath the abdomen) to propel itself. It is released like a spring when the springtail wants to jump.
(no larger image)
Despite their size, springtails are actually very common insects. They are found in soil, leaf litter, lichen, under bark, decaying plant matter, and other areas of high moisture. They are found indoors in damp areas of high moisture, e.g. around plumbing leaks and damp basements. They can also be found in the soil of overwatered houseplants. The abundant rainfall that most areas in Minnesota received during spring and early summer has contributed to the high springtails numbers now. Springtails feed on fungi, pollen, algae, or decaying organic matter. Springtails vary in shape and can be either slender or stout. They also are found in many colors, such as white, gray, black, iridescent green, yellowish and reddish. People have most commonly see slender, gray springtails.
Although people can find springtails in large numbers, they essentially cause no damage and are just nuisances. If springtails are a problem, first try to dry out moist areas as springtails do not tolerate dry sites. Outdoors, remove leaves, mulch, moist wood, or other potential sources of springtails. As the amount of rain lessens, this will naturally reduce springtails. Indoors, use a dehumidifier or make any structural changes necessary to reduce moisture and springtail numbers. Although it may be tempting to spray an insecticide, the products available to homeowners are not very effective against springtails.
Get the low down on this month's insect pests at
How's That Pronounced??
Recently I was reviewing some notes from the Arb Line desk and saw a question regarding the proper way to pronounce weigela. There are certainly a few horticultural pronounciation posers and an entomological poser or two out there.
Buddlea in Maryland
Ok, weigela is pronounced why-GEE-la. My botanical dictionary calls it VIE'-ge-la, but the author is British. Merriam-Webster says wI-jE' l&, using the ampersand because there's no upside down "e" ASCII character.
Another poser is cotoneaster, pronounced ko-TONE-ee-aster. Nope, not cotton-easter. It's a shrub whose most often identifying trait is a heavy scale (insect) infestation.
Cotinus is ko-TIE-nus but better known as smoke bush. It's marginally hardy in zone 4.
Buddleia is BUD-lee-a and really isn't hardy here. It's basically a die-back shrub in zone 4 which would make it a die-off shrub in zones 2 and 3.
A friend recently gave me a flowering quince. I had to dig a bit to find how that genus is pronounced. The aforementioned botanical dictionary gave the genus name under the common name listing but omitted the genus listing and subsequent pronounciation (oops). Chaenomeles japonica is the scientific name, and kee-NOM-e-lees is how garden expert Ken Druse indicates the genus name is pronounced.
How you pronounce clematis depends on where you were raised. Some of us call it cle-MA-tis others, CLEM-atis. The dictionary has both.
But peony is only supposed to be pronounced PEE-eh-nee, not pee-OH-nee. The genus is Paeonia, pronounced pie-ON'-ee-a.
It's easy to read a nursery tag wrong. I was once asked about "granola maple". It turns out he meant a ginnala maple. (A colleague suggested the client plant it next to a brown sugar maple.)
Aphids are A-fids, not AF-fids. There seem to be a lot around this year but then plants have been badly stressed.
Doesn't matter if you have one or a dozen, but thrips is thrips. They're fairly small so they're hard to see.
Of course those of us who work with plants for a living are hort-i-cult-ur-ists, not hort-i-cul-tur-AL-ists.
Note: Experts don't always agree on which syllable is accented. The intent here is not to attempt a definitive pronounciation guide, just to provide at least one acceptable option.
July Garden Calendar
Compiled from conversations with Bob Mugaas, Nancy Rose, Patrick Weicherding, Regional Extension Educators
Trees and Shrubs:
Gaillardia like hot sunny sites. |
Major danger for oaks and elms has passed but given the odd spring, it's still best to wait until fall for pruning.
While late winter pruning is best for most trees, removing storm-damaged and dead wood now is ok.
Dutch elm disease is still rampant. Monitor your trees for wilting and yellowing. By the time you see wilting and yellowing, it probably too late for treatment.
Water, water, water!!! Any trees or shrubs planted 5 years ago or less really need to be watered. Water needs to penetrate the soil to a depth of 6 to 8 inches. On recently planted trees and shrubs, be sure to water the root ball not primarily the surrounding soil. The roots are still concentrated in the root ball.
Mulch, mulch, mulch. Three to four inches of woodchips will halp preserve soil moisture.
Wooly aphids and other aphids are busy feeding in deciduous trees. You will see frass (insect feces) inside curled leaves. Webbing indicates spider mites on deciduous trees.
Anthracnose damage is still present but new growth is less likely to be infected.
Apple scab infection, which causes yellowing and dropping of leaves, may be less severe this year if the dry spell continues.
Finish off any tree or shrub fertilizing chores as you really want to suspend any fast-acting fertilizer applications from mid-July into fall. Trees and shrubs are hardening off in preparation for winter.
Now that weather is drying, lawn are becoming water-stressed. If you want to keep your lawn green and actively growing, you'll need to apply 1 to 1.5 inches of water per week. If you have an irrigation system, your plants are accustomed to frequent water and need it. You can add a day between watering zones to conservee.
If you have sandy soil or hard-packed clay, apply less water per watering but do it more frequently. Sand drains too quickly and water pools on clay soils.
Don't panic if the lawn dries a bit as it might be beneficial in stimulating root growth. Hormonal signals to roots at a point in mild drought cause root tip tissue cells to divide and grow, creating more roots.
If your lawn turns a dull blue-grey color and if you leave footprints when you walk across it, you need to water.
Deficite irrigation is the concept of applying somewhat less than the water lost. Instead of applying an inch of water per week, it could be an inch every 2 weeks.
When it's really hot, dry and windy, you'll need to shorten the interval between waterings as the plants will dry out faster.
Avoid herbicide applications. Crabgrass control should probably be avoided as such hot temperatures can cause the turf to yellow.
Turf grasses will take drought stress and not die. Just remaember to mow high, 3", with a sharp blade.
Fruits, Flowers and Veggies
It's too late to bag apples to protect against apple maggot, but you can continue to monitor adult activity with sticky traps and spray as needed. Read the guidlines at: http://www.extension.umn.edu/distribution/horticulture/DG1007.html
Bearded iris can be divided. |
June-bearing strawberries may need to be renovated. See the article in the July 1, 1999 Yard & Garden Line News: Renovating Junebearing Strawberry Plantings.
It's perfectly ok to mulch the veggies garden with thin layers of grass clippings, providing they've not been treated with herbicide. Compost works well, also.
Iris can be divided and replanted starting now. See Iris For Northern Gardens for more info. As you dig them you may find borers in the soil in their dark brown pupae. The Yard & Garden Brief on iris borers, at http://www.extension.umn.edu/projects/yardandgarden/ygbriefs/e122irisborer.html, will provide more info. Cygin is not longer available, so see the update at:
See previous years' July to-do lists:
Mark Seeley, state climatologist, noted in his weekly weather newsletter today, that this warm July was not predicted by NOAA's prediction center. It's a bit warm for many of us and too dry for most of us but we're still better of than El Paso where a heat wave produced 28 days over 100.
Willow amsonia and pink|
Master Gardeners continue to receive lots of questions regarding storm or winter-damaged trees. Patrick's article should help people decide what to do.
Bob Mugaas, who co-authored the lawn care herbicide article last issue, will provide a garden companion piece to the lawn care article in a future issue. Nancy Rose has a piece on small shrubs ready for us. Julie Weisenhorn will conclude the landscaping project story in a future issue. Patrick Weicherding will write about on-going research at the U that's evaluating whether butteflying, scoring or teasing apart circling roots in container grown trees makes a difference in the establishment of trees.
Please feel free to cut and paste any of the articles for use in your own newsletters. All we ask is that you give our authors credit.
Back issues Yard & Garden Line News are on the Yard & Garden Line home page at www.extension.umn.edu/yardandgarden/.
Deb Brown answers gardening questions on Minnesota Public Radio's (MPR) "Midmorning" program on the first Thursday of every month at 10 a.m. The program is broadcast on KNOW 91.1 FM, and available state-wide on the MPR news radio stations. (Scroll down for map.)
For plant and insect questions, visit http://www.extension.umn.edu/askmg. Thousands of questions have been answered, so try the search option in the black bar at the top left of the board for the fastest answer.
If you would like to receive an e-mail reminder when the next issue of the Yard & Garden Line News is posted to the web, just send an e-mail to:
email@example.com (note: the second E in listserve is omitted), leave the subject line blank, then in the body of the message, type: sub yglnewslist or to unsubscribe, enter: unsub yglnewslist
Yard & Garden Line Project Coordinator
University of Minnesota Extension Service Home Page
In accordance with the Americans with Disabilities Act, this material is
available in alternative formats upon request. Please contact your
University of Minnesota county extension office or, outside of Minnesota,
contact the Distribution Center at (612) 625-8173.
The University of Minnesota Extension Service is committed to the policy that
all persons shall have equal access to its programs, facilities, and employment
without regard to race, color, creed, religion, national origin, sex, age,
marital status, disability, public assistance status, veteran status, or sexual