American Elm Tree

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Ulmus americana, generally known as the American elm or, less commonly, as the white elm or water elm, is a species native to eastern North America, naturally occurring from Nova Scotia west to Alberta and Montana, and south to Florida and central Texas. The American elm is an extremely hardy tree that can withstand winter temperatures as low as −42 °C (−44 °F). Trees in areas unaffected by Dutch elm disease (DED) can live for several hundred years. A prime example of the species was the Sauble Elm, which grew beside the banks of the Sauble River in Ontario, Canada, to a height of 43 m (140 ft), with a d.b.h of 196 cm (6.43 ft) before succumbing to DED; when it was felled in 1968, a tree-ring count established that it had germinated in 1701.

For over 80 years, Ulmus Americana had been identified as a tetraploid, i.e. having double the usual number of chromosomes, making it unique within the genus. However, a study published in 2011 by the Agricultural Research Service of the USDA revealed that about 20% of wild American elms are diploid and may even constitute another species. Moreover, several triploid trees are known only in cultivation, such as 'Jefferson', are possessed of a high degree of resistance to DED, which ravaged American elms in the 20th century. This suggests that the diploid parent trees, which have markedly smaller cells than the tetraploid, may too be highly resistant to the disease

Germination Care

American elm seeds typically germinate shortly after they reach the ground, although the seed may lay dormant until the following spring. Seeds can germinate under low light conditions although germination success increases under moderate light. Seeds can also persist in saturated environments for extended periods with little effect on germination. American elm seedlings can establish on a variety of substrates including – moist litter, moss, and decayed wood, however, germination is most likely on mineral soil. Early development is best on moist soils but not saturated soils. As seedlings mature their drought tolerance increases and relative to other bottomland species they are intermediately tolerant to complete inundation.

Main Benefits

A fiber obtained from the stems is used in making paper. The stems are harvested in spring, the leaves are removed and the stems steamed until the fibers can be stripped. The outer bark is removed from the inner bark by scraping or peeling. The fibers are cooked for 2 hours with lye and then beaten with mallets. The paper is beige in color. The inner bark is very fibrous and is used in making string and strong ropes. The bark has been used to make various containers, including those used for gathering maple syrup. Wood - hard, strong, heavy, durable, coarse grained, shrinks moderately though it tends to warp and twist, it bends well and is difficult to split. The wood is very durable in water. It weighs 40lb per cubic foot and is harvested commercially for flooring, wheel hubs, cooperage, agricultural implements, and many other uses.

Planting Care

You can plant container-grown trees any time of year. Bare root, balled and burlapped elms are best planted in spring or late fall. Don’t amend the soil in the hole at planting time unless it is very poor. Add a little compost to the fill dirt for poor soils. Wait until next spring to fertilize an elm tree. Zone 3 - 9. Soil Preference: Moist, well-drained soil. Tolerances: Dry sites, Alkaline soil, Clay soil, Road salt.

Ideal Climate

Elms prefer full sun or partial shade and moist, well-drained fertile soil. They adapt to wet or dry soil as well. They make good street trees because they tolerate urban conditions, but keep in mind that planting an elm tree near sidewalks can lead to cracks and raised areas. Mulch the tree immediately after planting. Mulch helps the soil hold moisture and reduces competition from weeds. Use a 2-inch layer of light mulch such as shredded leaves, hay, or pine needles. Use 3 inches of bark mulch. Water young trees weekly in the absence of rain.