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Elm Trees Make a Comeback
Triumph, a disease-resistant elm,
was developed in Illinois.
The Comeback
(Originally Published September/October 2004)
MARK TWAIN once protested that reports of his death were greatly exaggerated. If elm trees could talk, they might say the same.
Elms have long been revered for their vase-shape form and resistance to heat and drought. Starting in the 1930s, Dutch elm disease hopped the Atlantic on European logs bound for a Cleveland sawmill. Since then, a high percentage of elms has died from the fungus spread by the elm bark beetle and through roots of adjoining trees.
Today, the trees are poised to return, thanks to developments by researchers such as Dr. George Ware. At the Morton Arboretum in the western Chicago suburb of Lisle, Illinois, Dr. Ware oversees the largest collection of elm species in the country—possibly in the world. He discovered that more than 20 species of elms from China possess a built-in resistance to Dutch elm disease.
In the 1970s, Dr. Ware contacted a Chinese forester to collect and ship elm seeds to him. As the Chinese seedlings grew, researchers repeatedly injected them with the Dutch elm fungus.
"Every American elm in testing got sick and died, but not a single elm with Asian ancestry suffered," Dr. Ware says. Even better, the Asian elms showed resistance both to damage from elm leaf beetles and to "elm yellows," another devastating disease.
Most of the Asian elms lacked the graceful shape of the American variety, but one seedling looked like a promising substitute. "The David elm (Ulmus davidiana) looked like a super-healthy American elm, with a similar vase-like shape and deep-green, glossy leaves," Dr. Ware says.
The David elm grew a little slower and was also about 15 feet shorter than the American elm's 70 feet, which makes it a good choice for most urban landscapes. It showed good tolerance in tough conditions such as poorly drained clay soil and drought. Best of all, it proved winter-hardy in the coldest parts of the Midwest.
Two hybrids developed by Dr. Ware also resemble American elms—only better. Both Triumph and Accolade exhibit disease resistance inherited from their Asian parents, plus glossy leaves and attractive shapes.
You may be able to order elms from your local nursery. Few mail-order firms carry all the varieties. One that does (in limited quantities): Arbor Village, Box 227, Holt, MO 64048 (www.arborvillagellc.com; catalog $1).
