Unique Features: The Valley Forge elm was released by the U.S. National Arboretum in 1995.  It has excellent resistance to Dutch Elm Disease and the Elm Leaf beetle. It is, however, susceptible to Phloem Necrosis and Verticillium Wilt which can be serious problems. This is a fast-growing tree which will need a lot of room to grow, and regular pruning (every 3-5 years) while the tree is young (<25 years) is beneficial.  This elm does produce seeds which are mostly sterile.