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- Cautious garden banter
- Giving Thanks for Gardening
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- Holes in trees – wood borer or woodpecker?
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The Homeowners Column
Common Problem Trees To Use With Caution
Extension Educator, Horticulture
Problem child - everybody has one or knows one. Problems predictably follow them along with the headaches and the sound of broken dishes. But maybe they are not really problem children. Maybe they just haven't found the place where they can flourish. Some trees seem like problem children with their diseases and bugs and the sound of broken branches. Trees are not bad trees; we just haven't placed them where they can flourish.
First select the right tree for the right spot. Give power lines plenty of clearance from large trees. You do the math- A tree with a mature height of 80 feet will soon engulf a 30 feet tall power line.
Secondly, when planting trees do some homework to determine the common problems associated with a tree in our area. Just wanting fast shade is not a good reason to plant a problem child, unless you are planning to remove the tree once a more desirable tree gets larger. With proper care such as watering during drought periods, mulching and regular fertilization, durable trees will provide fairly quick shade.
Many trees should not be planted as shade trees in lawns, but are usable trees around ponds and in less manicured areas. They can also provide wildlife habitat and food in natural areas.
Silver Maple - A tree often inherited. Probably one of the best trees for areas with poor growing conditions where few other trees would survive. However they can cause sidewalks to buckle and can clog drain tiles. Silver maples are fast growing and may reach 10-12 feet tall in 4 to 5 years. Unfortunately fast growth means weak wood which translates into limbs all over the yard from wind, ice and snow damage. If you have inherited a silver maple, they can be nice shade trees, but they require regular maintenance by a certified arborist.
Sycamore - Like most kids, they are always dropping something. They have leaves like shoe leather (from a very large shoe). The tree continually sheds its outside bark like a dog in summer and they have fuzzy seed balls that shower down. They can reach 100 feet tall with an equal spread - much too large for a street tree and for most lawns. The regular infection of the fungal leaf disease, anthracnose, keeps sycamores bare of leaves until mid to late June and causes twigs to continually fall.
Sycamores are magnificent trees with beautiful white bark when they are situated along rivers and in flood plains which is where they should stay.
Siberian Elm - Numerous diseases, brittle wood, elm leaf beetle and just plain messiness with no ornamental attributes. Don't confuse this with the far superior Chinese elm, Ulmus parvifolia. I'm having a hard time determining the redeeming value of Siberian elms. Firewood, perhaps? In his book Manual of Woody Landscape Plants Michael Dirr comments about Siberian elm as "one, if not, the world's worst tree". Maybe there really are bad trees.
Other problem children include:
Bradford Pear Pyrus calleryana 'Bradford' - poor branch structure, too many branches arising from common site on trunk, narrow branch angles, tends to split apart as it ages, needs regular pruning to develop structure. 'Chanticleer', 'Redspire' and to some extent 'Aristocrat' show same problems.
European Mountainash Sorbus aucuparia or American Mountainash Sorbus americana - borer insects, fire blight disease.
Pine, Scotch Pinus sylvestris - pine wilt disease.
Princess Tree Paulownia tomentosa – brittle wood, drops leaves, twigs, flowers and seeds. Flower buds often get killed by frost in central Illinois. Plant often featured in slick newspaper ads.
Russian-olive Elaeagnus angustifolia and Autumn-olive E. umbellata - canker and verticillium fungus wilt disease, very weedy, a scourge in native areas.
For a more extensive list of problem trees and selecting trees check out: