Every time Mark Vitosh sees another 'Autumn Blaze' maple planted in the landscape, he gets slightly uneasy.
Maples make up more than one third of all trees in Iowa communities, creating great risk of tree loss should a new insect or disease target maples, Vitosh, a district forester for the Iowa Department of Natural Resources, or DNR, explained.
In response to the threat of the ash tree-killing insect emerald ash borer, the DNR conducted inventories over the past several years of about 350 small communities (fewer than 5,000 people) and found that, overall, about 17 percent of the street and park trees in these communities is ash while about 34 percent to 37 percent is maple trees.
"More maple is not a good idea," Vitosh said.
Jeff Ies, chairman of the horticulture department at Iowa State University, Ames, agrees.
"In general, we have over-planted the sugar maples, like 'Autumn Blaze,'" he said. "Every time you start loading up the landscape with one kind of tree," you invite decimation, he said.
That is what happened with American elms killed by Dutch elm disease and what is happening now with ash and emerald ash borer.
But homeowners in the market for a tree often pick 'Autumn Blaze' "because they are familiar with it and know that it grows well in this area," Kate Terrell, owner of Wallace's Garden Center and Greenhouses, Bettendorf and Davenport, said.
However, in addition to the over-planting aspect, "over time, red maples can get so dense that they shade out all the grass, and surface rooting can be a problem with heavy clay soils," she said.
So, homeowners looking for a new deciduous (loses its leaves) landscape tree might want to consider something else.
Tulip tree, London plane tree (a cross between American and European sycamores) and Kentucky coffee tree are three choices for tall landscape trees that John Vance, city arborist for the city of Davenport, has been planting to replace ash trees that he and his crews have been cutting down from public property because they are infested with the emerald ash borer.
His choices for smaller, understory trees or tall shrubs are golden rain, redbud, crabapple and Japanese tree lilac.
Bald cypress, black gum and ginkgo are Iles' top three alternative picks in addition to bald cypress. He also likes many of the oaks.
While homeowners may have heard about various problems affecting oak trees, Iles said he wouldn't shy away from planting them.
"Oaks in general are a fantastic tree," he said. Good varieties include bur, white and swamp white oak. Again, hybrids are being created; "Regal Prince" is a cultivar he would recommend.
Other types of oaks include the northern red, pin and chinkapin.
New elm varieties resistant to Dutch elm disease also can be considered, Terrell, of Wallace's, said. She recommends bald cypress and birch for wetter areas.
Beech and hornbeam trees are both "under-utilized," Andy Kay, owner of The Green Thumbers, Davenport, said." Beech has "gorgeous," smooth gray bark and the hornbeam is a little shorter and narrower than many landscape trees, which can be a plus in many urban settings, he said.
Smaller, more-narrow and disease-resistant varieties of old favorites are being hybridized with amazing speed, and are good choices for smaller yards, he said.
The DNR has a publication of recommended alternatives that is available online by typing in "rethinking maple" and "iowa department of natural resources" into a search engine.
River birch is another possibility, Kurt Meyer, owner of Meyer Landscape & Design, Moline, said. It is resistant to the bronze birch borer that harms white birch trees. Amur maackia is another consideration, he said. The tree gets about 30 feet tall and has flowers in spring.
Terrell summarizes the recommendations when she says, "the thing to consider when planting a tree is knowing the conditions of where you are going to plant it.
"Once you establish that, then we can help select the tree that will do best in that area. People should consider light exposure, soil conditions, and the mature size of the tree."
Vitosh reminds people that planting different kinds of trees means planting different genera, not simply species. That is, not three kinds of oaks, but an oak, a locust and a bald cypress, for example.
He recommends visiting various arboretums, such as the Bickelhaupt in Clinton, and going online to look at pictures. "Make some effort to find a tree that will meet your needs," he said. "Ask yourself, 'Is this a tree I want in my yard?'"
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