blooming flowers climber in tree to prune beneficial mushrooms close up of lady bug on leaf japanese maple being pruned
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The Arbor Advisor
FALL 2003
> Featured Tree: Prairie Fire
> Tour des Trees
> Armillaria Root Rot
> Maintenance Tips for Fall and Winter

Spruce spider miteThe Collier family — Brandon, Terril, Logan and Janet — along the Tour des Trees route.

Tour des Trees:
A Collier Family Affair

The Colliers made this year’s Tour des Trees 600-mile bicycle marathon a family affair as wife and partner, Janet, joined Terrill and sons Brandon (16) and Logan (14), on the 7-day tour which began in Ottawa, Canada, swung through upstate New York and Vermont, finishing in Montreal.

Besides raising funds for the International Society of Arboriculture’s (ISA) Tree Research and Education Endowment Fund, the group of about 80 arborist riders from throughout the US and Canada participated along the way in a number of tree plantings, including ones in Lake Placid, New York and Stowe, Vermont.

Terrill and family became the first family entrants in the annual event which precedes the annual ISA convention, which was held this year in Montreal. Thank you to all those who helped support this event with your generous donations.

Hot-pink spring blossoms of the disease resistant Prairie Fire Crabapple are long lasting.

Flowering Crabapple: Prairie Fire

There are few trees that can approach the beauty of a crabapple in full bloom. But crabapples have had a reputation for being disease prone and having messy fruit. However by careful variety selection, there are several disease resistant (and beautiful) crabapples to choose from. They are valued for their smaller size, flowers and fruit that are attractive to wildlife.

One of the best red leafed crabs is a Prairie Fire. This crabapple has impressive landscape appeal; long lasting hot red-pink flowers, excellent small red persistent fruit, attractive reddish bark and small form. The foliage emerges purple then gradually becoming reddish green. Best of all this variety is very resistant to diseases including scab and mildew. Prairie fire grows upright while young then rounded to 20-feet tall and wide. This is an impressive small tree with 4-season appeal and should have a special place in most landscapes.

Armillaria Root Rot

Armillaria (or shoestring root rot) is a fungus that rots the roots of many different trees and plants. Most often it is found infecting oaks, dogwoods, rhododendron, lilac and conifers like Douglas fir but is reported on over 700 species of plants. Plants that are under stress and are growing poorly are most susceptible. Sudden changes in root environment can trigger infection. The classic situation that I see killing trees, is installing turf and irrigation in the root zone of an oak or fir and then over watering.

(Left) Dead Oak from Armillaria due to changed root environment from lawn installation and over-watering.
(Right) Mushrooms from the Armillaria fungus appear in the fall at the base of infected trees.
Symptoms include a general decline of the plant over several years, poor growth, stunted foliage, dieback of foliage and branches. Plants will suddenly turn brown and die during the summer. Examine the lower trunk or root crown of affected plants. White fungal growth (mycelia) is found underneath the bark killing the cambium. Additionally the fungus forms black string-like strands or shoestrings (rhizomorphs) under the bark or in the soil. Honey colored mushrooms may also develop at the base of the plant in the fall.

There is no cure for severely affected plants. They should be removed along with the stump. Armillaria can survive for many years on dead stumps and roots. Slightly affected plants should have soil removed from the root crown and allowed to be air-dried. Avoid watering the base of the trunk; keep this area as dry as possible. Replant with species that are resistant such as; crabapples, ginko, magnolia, sweet gum, incense cedar and pines. Often it takes an expert to diagnose the root rot. Our technique of exposing the root crown using the Air-Spade tool allows for easy diagnosis of Armillaria or other root problems.

Maintenance Tips for Fall and Winter

OK, so we’re a little late telling you that fall is the best time to plant trees and shrubs because they have all winter and early spring to grow roots and become established before summer heat and dryness come stalking. There’s still time, if you hurry, but the next best time is spring.

We’re not late, though, in reminding you that late fall and winter tree and shrub fertilization is important to maintaining their health and vigor. It replenishes nutrients used up during the growing season, and where top soils have been removed during construction. It also adds nutrients not originally in the soil. Our subsurface fertilizing method injects nutrients into the root zone for easy uptake.

Dormant Pruning
Dormant season is an excellent time to prune fruit trees, and large shade and native trees. It’s easier to see the branch structure so we can prune to:
  • Thin to decrease wind resistance and damage from snow and ice

  • Remove dead, diseased or damaged branches

  • Prune and thin overgrown, unsightly trees to shape

  • Train trees to a desired shape

  • Prune and invigorate old or neglected trees (We’re still keeping Vancouver’s 176-year-old Apple Tree going!)

And speaking of dormant...
Effectively controlling certain insect and disease problems is a year ‘round task. In fact, dormant treatments may be the only effective way to control a problem (peach leaf curl disease, for instance).

In the hands of a professional, relatively non-toxic horticultural oils, coppers and daconil are considered acceptable organic control materials. They can be effective for the following:

Effective Dormant Plant Treatments:

Material: Use For:
Horticultural Oils Insect control for scales, mites, aphids, and various insect eggs
Copper Fungus control, bacterial diseases such as peach leaf curl, coryneum blight (shot hole), bacterial (Psuedomonas) blight
Daconil Fungicide used on stone fruit and flowering fruit trees to help control leaf spot diseases, peach curl, and anthracnose

A word of caution, though: Dormant treatments aren’t silver bullets. Trees and shrubs still need year ‘round care to control disease and insect problems.

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