Appearance: Deciduous tree, 30 – 60′ high with an open rounded crown and slender, spreading branches. Bark is dark gray and shallowly furrowed on a mature tree. Silver-gray twigs have a zig-zag shape with a leaf bud at each turn.
Leaves: Alternate, small, (1- 2″), elliptic, toothed, short-pointed at the tip, slightly uneven at the base (much less than American elm).
Flowers: Greenish, lacking petals and occurring in small, compact, drooping clusters of 2 – 5, appear before leaves develop.
Fruit: Winged, round, and smooth, contains on seed; fruit hangs in clusters.
Reasons Siberian Elm is a Problem:
- Especially proficient at invading disturbed prairies, being able to dominate new locations, especially recently planted prairie restorations, in just a few years.
- Seed germination rate is high and seedlings establish quickly in sparsely vegetated areas.
- Grows readily in disturbed areas with poor soils and low moisture.
- Still sold commercially as a shelter belt and windbreak tree.
A native of eastern Asia, Siberian elm was introduced to the U.S. in the 1860s for its hardiness, fast growth, and ability to grow in various moisture conditions. A large tree line composed mostly of Siberian elms was removed in Cowling Arboretum between the 2004 and future 2007 prairie plantings in the summer of 2006. The rapidly spreading seedlings initially were very prevalent on the field edges but management burning has decreased their presence. Other Siberian elms were removed in the fall of 2007 from the area surrounding the 2007 field of direct tree seeding in the northeast of the Arboretum. Once this former field was taken out of cultivation, young Siberian elms would have out-competed the slower growing red and white oak, black cherry, green ash, butternut hickory, black walnut, and eastern wahoo trees that were planted there.
Cowling Arboretum Procedures for Removal:
Procedures are similar to buckthorn, but Siberian elm is rarely in as concentrated of patches, requiring less disturbance for full eradication. After trees are cut herbicide applied to the stumps is a successful method of killing Siberian elm. Trees can also be girdled, and herbicide applied to the sapwood and outer heartwood.