Thanks to the plant cloning work of tree geneticist Alden Townsend, the prognosis for American elms is now good. In the late 1990s approximately twenty-five years of plant cloning work on American elms came to fruition when the announcement was made: Townsend had finished cloning two new strains of American elms. These plant clones are resistant to Dutch elm disease. Named Ulmus americana "Valley Forge" and Ulmus americana "New Harmony," Townsend's plant clones are now on the market. And the plant cloning work of tree geneticists continues, in hopes of developing new American elms that will be even more resistant to Dutch elm disease.
But for now, if you are not able to purchase one of these plant clones of American elms, or if you are trying to save a long-established tree, follow these guidelines:
- Prune dead or dying branches off American elms, from fall to late winter. This procedure, called limbing, is best handled by professionals.
- But avoid pruning American elms from April through August. The elm bark beetle is attracted to freshly cut elm and is most active during this period.
- Be on the lookout for the signs of Dutch elm disease. Leaves of infected American elms will wilt in the summer. They will first turn yellow, then curl, and finally become brown. The signs usually first appear in the crowns of American elms.
- If signs appear, dispose of infected American elms properly. In rural areas they may be burned. In urban areas, take them to a designated disposal site.
Note that American elms are considered one of the worst trees to plant for allergy sufferers. But for those who are not allergy sufferers, American elms make for splendid specimen plants. American elms are cold hardy to zone 3.
Humans will not be the sole winners if the former ubiquity of the American elms is restored through plant cloning work. For Baltimore orioles American elms had always been a favorite nesting tree. The male oriole is one of nature's most striking birds, with screaming orange markings punctuated by jet black plumage. Baltimore orioles prefer American elms for nesting because of the drooping habit of the trees' branches. Orioles' nests hanging from the ends of branches of American elms are nearly impossible for predators to access.
Bruce Carley (see Page 1) tells us how the cities of Portland, Maine and New Haven, Connecticut were once home to so many American elms that each locale earned the title, "City of Elms," long before the words, "plant cloning" had ever been heard. But thanks to plant cloning, the prospects are now better that people will someday honor your hometown with the epithet, "City of Elms." Plant clones may yet restore "Elm Street, USA."
