The graceful and statuesque American Elm (Ulmus americana) once lined almost every street and town square across the country, providing a familiar vase-shaped canopy that many people today still remember from their youth.
But by the 1960s, the American elm was only a memory to most Americans because of Dutch elm disease which eradicated millions of American elms, many of which dated back to the 1700s. The disease was introduced to the US through a fungus carried and spread by the tiny elm bark beetles, which entered an American port in a shipment of elm logs in 1930.
Elm Trees Reappear on American Landscape
However, the Elm Research Institute (ERI) has been hard at work since the 1970s developing an elm tree that could resist the disease; the American Liberty Elm (Ulmus americana "libertas") is the first disease-resistant American elm with a pedigree and warranty against Dutch elm disease.
The tree, named after the famed “Liberty Tree” which was an elm that stood in Boston during the American Revolution, is a product of a 40 year research project under the auspices of the ERI and the University of Wisconsin.
Liberty Elm Cloned from Disease Resistant Elms
What distinguishes the Liberty Elm from those elms that succumbed to Dutch elm disease is that the improved tree has is a smaller cell structure than its predecessors that prevents the disease from entering the tree, making it resistant. The Liberty elm is actually cloned from trees the organization genetically screened to develop resistance.
While there is no known American elm variety that is 100 percent immune to Dutch elm disease, the Liberty elm is extremely resistant to the disease.
Each Liberty tree is backed with a lifetime warranty and ERI will replace any American Liberty Elm tree lost to Dutch elm disease (the replacement elms are at least 6 feet tall); to date fewer than 1% of ERI trees have been lost because of Dutch elm disease.
The organization states on its Web site that other elms have appeared on the market, but they often do not carry a warranty against Dutch elm disease.
There are Dutch elm disease-resistant elms imported from Asia, such as the Chinese elms, but are shorter than American elms and are slower-growing trees with a base-shaped crown that is closer to the ground. American elms, which flower in the spring are faster-growing (at about 2-5 feet per year), and can reach heights of 80 to 100 feet.
Elms: Beautiful in the Landscape
In the landscape, the American Liberty Elm displays a classic elm form, and is perfect for many landscape designs, including elm-lined drives, elm groves and specimen elms. As an elm matures it displays wide canopies to heights that afford clear views of the architectural details of buildings and deep shade for people to enjoy.
These disease-resistant elms are also being incorporated into the new Traditional Neighborhood Design communities (or “New Urbanism”), neighborhoods that are designed to be pedestrian friendly and have the feel of “old” communities.
National Movement to Re-Elm America
The Liberty elm has been planted in 1,000 communities since it was introduced in 1983, mainly through contacts with mayors throughout 40 states to encourage communities to sign up as “municipal members” of the ERI.
The organization has also rounded up the Boy Scouts to plant them throughout the country. Today, many Liberty elms grow in prominent public areas such at U.S. Capitol Building, Statue of Liberty, Daniel Webster Birthplace and Golden Gate Park.
For more information on the American Liberty Elm, visit the Elm Research Institute, Individuals may also get a free 2-3 ft. tree with a $45 membership.
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