Dutch Elm Resistant Prairie Expedition American Elm (Ulmus americana 'Lewis & Clark')
The stately American elm once lined the streets of most American cities. Dutch Elm Disease wiped out as many as nine out of ten of these trees since the 1930’s. This loss taught us the importance of diversity in landscape design and street tree plantings. There is, however, good news for those that miss the American Elm.
Scientists found that some of the surviving older American elms have been tested and appear to be resistant to Dutch Elm Disease. These have led to new introductions of disease resistant American Elms.
Prairie Expedition was one, propagated from a lone survivor in a stand of American elms killed by Dutch Elm Disease. It has the typical umbrella shape and grows 60 feet tall and 40 feet wide. The lustrous green leaves turn yellow in fall. Hardy in zones 3 to 9, it thrives in full sun and moist rich soil.
A bit more information: Earlier introductions of Dutch Elm Disease (DED) tolerant varieties were hybrids like Patriot that were crosses between American and Asian elm varieties. Most of these hybrids did not have the desirable umbrella shape of the American Elm. Watch for future research results and new DED resistant elm introductions.