Siberian elm (Ulmus pumila) is a hardy, fast growing, mid-sized, deciduous tree or shrub from China, eastern Siberia, Manchuria, and Korea. Siberian elm can get up to 70 feet tall and has an open crown with upward-growing branches and many flexible, brittle branchlets that easily break off. Leaves grow alternately on branches, are heart-shaped at the base and taper to a long point, with small teeth along the entire margin. Reproduction is by seed, primarily dispersed by wind, but also by water, animals, and in the undercarriages of equipment and vehicles. Flowers are cross-pollinated by the wind, and trees can be self-fertilizing. Small clusters of 3-15 perfect flowers are produced at intervals along the preceding year’s branches. The blooming period occurs from early to mid-spring before the leaves develop, lasting about one week. Seeds develop in a light green, oval-shaped, and flattened wing-like fruit known as a samara. Siberian elm does not tolerate flooding and seldom invades mature forest because of its high requirement for sunlight. Siberian elm can dominate new locations in just a few years due to its adaptability, high rate of germination, and rapid growth.
There are few occurrences of this species documented in Colorado. View the known North American Distribution Map. If you are aware of infestations that are not represented, please report your sighting. Register for an EDDMapS account, then select "Report Sightings". Please include photos with your submissions.