Elm Tree Planting and Care

Elm trees grow from 60 to 90 feet tall and produce dark green leaves that measure from 3 to 6 inches long and turn a brown-yellow in the fall. The elm tree population has been decimated by the Dutch Elm Disease which was brought to the United States from Europe in the 1930's and quickly spread throughout the country. Growers are developing varieties that have a greater resistance to the disease.

The elm tree is native to eastern North America from Canada to Florida. The tree is hardy in USDA zones 2 through 9. Elm trees can be planted at any time of the year as long as the ground is not frozen. Just give them a
moist, fertile soil and full sun. The trees are salt tolerant, so you can plant them in coastal areas. Elms are tolerant of urban pollution and adaptable to both wet and dry conditions. The tree is home for several species of butterflies and birds and small mammals will make a meal out of the seeds.

The main reason Dutch Elm Disease is so serious is its ability to spread from one tree to another via the root system. The disease is a fungus that clogs up the vascular system, the system that brings the water from the ground up to the crown. The tree does not get water, wilts and dies.

Insecticides are available to combat the beetles that spread the disease and the tree can be injected with a preventative fungicide, but the best course of action is to plant varieties of elms that are naturally resistant to the disease. The United States Department of Agriculture recommends planting more than one variety to further limit the chance of the disease taking hold in case one of them is not as resistant as it is thought to be.

American elm (Ulmus americana L.) is not a good choice and is considered the most susceptible. Winged elm (Ulmus alata Michx.), September elm (Ulmus serotina Sarg.), Slippery elm (Ulmus rubra Muhl.), rock elm (U. thomasii Sarg.), and cedar elm (U. crassifolia Nutt.) range from susceptible to somewhat resistant. These are all native to North America and none of them are 100 percent resistant. European and Asian varieties are less susceptible, but again, they are not immune.

Scientists have been developing cultivars by cross breading the strongest elms in an effort to develop disease resistant elms and then cloning the best. The Princeton Elm, the American Liberty, Independence, Valley Forge and New Harmony are clones with the most promise and should be available from retailers.

United States Department of Agriculture

University of Connecticut