American Elm

American Elm is a large deciduous tree native to eastern North America, capable of reaching 100 feet tall with a vase-shaped, arching canopy that spreads 82 feet or more at maturity. You recognize the characteristic form by its tall trunk supporting broadly spreading, arching upper branches that create an umbrella-like silhouette. The leaves are alternate, simple, 7.5 to 15 centimeters long, ovate-oblong with unequal bases and double-serrate margins; they are glossy dark green above and turn yellow in fall. Spring flowers appear before leaves and are inconspicuous; the anthers are bright red while styles and ovary are light green. Rounded, disc-like samaras (seeds) mature in early summer and disperse readily. Bark on younger growth is smooth, becoming rougher with age.

You will find American Elm performs well in full sun and adapts to a wide range of soil conditions, from acidic to mildly alkaline, though it prefers rich, moist loams. The tree tolerates both wet and dry sites, making it valuable for rain gardens and slope plantings. Its fast growth rate and ability to withstand urban conditions historically made it a common street and lawn tree, though this overplanting created vulnerability to disease. Many cultivars show good to excellent Dutch Elm Disease resistance; 'Princeton' and 'Jefferson' are focus-list selections available in trade. The tree suffers from multiple pests and diseases documented in the PNW, most notably Dutch Elm Disease (transmitted by bark beetles) and several defoliating insects. Monitor for bacterial wetwood, Nectria canker, bark beetle, elm leaf beetle, and elm leafminer activity.