Elm, Slippery

Ulmus rubra, the Slippery Elm, is a deciduous tree which can grow to 65 feet in height with a 20-inch d.b.h. trunk. The tree’s more upright branching pattern differs from the deliquescent branching of the American elm. Its heartwood is reddish-brown, giving the tree its alternative common name ‘Red Elm’.

The LEAVES are 4-6 in long and have a rough texture (especially above), coarsely double-serrate margins, acuminate apices and oblique bases.

The perfect, apetalous, wind-pollinated FLOWERS are produced before the leaves in early spring, usually in clusters of 10–20.

The FRUIT is an oval winged samara about 3/4 in long that containing a single, central SEED.

Slippery elm may be distinguished from the American elm by the hairiness of its BUDS and TWIGS (both smooth on the American elm) and by its very short-stalked flowers.

The WOOD of the slippery elm is used for the hubs of wagon wheels, as it is very shock resistant owing to the interlocking grain.

The tree is reputedly less susceptible to Dutch elm disease than other species of American elms, but is severely damaged by the Elm Leaf Beetle (Xanthogaleruca luteola).

The name rubra (red) alludes to the tree’s reddish wood, while the common name “Slippery Elm” alludes to the mucilaginous inner bark.

The mucilaginous inner bark of the slippery elm has long been used as a demulcent, and is still produced commercially for this purpose in the United States with approval for sale as a nutritional supplement by the U.S. FDA.