Slippery Elm
Scientific Name: Ulmus rubra
— pronounced UL-mus ROO-bruh
— Ulmus, Latin for elm; rubra, Latin meaning red, for the tree’s reddish heartwood
Elm Family (Ulmaceae), a group of trees and shrubs with mucilaginous substances in leaf and bark, found mostly in the north temperate zone
Other Common Names: Grey Elm, Red Elm, Soft Elm
Slippery Elm and American Elm (Ulmus americana), which both occur in the Preserve, are very similar, overlapping in their characteristics and preferred habitats.
The leaves of both elms have especially noticeable "drip-tips" (these enable leaves to shed water more quickly). The leaf’s base is asymmetrical, and its border is doubly serrate — that is, the border has teeth, and the teeth have teeth. The Slippery Elm’s leaves are rough to the touch on top and have wooly hairs on the underside.
— pronounced UL-mus ROO-bruh
— Ulmus, Latin for elm; rubra, Latin meaning red, for the tree’s reddish heartwood
Elm Family (Ulmaceae), a group of trees and shrubs with mucilaginous substances in leaf and bark, found mostly in the north temperate zone
Other Common Names: Grey Elm, Red Elm, Soft Elm
Slippery Elm and American Elm (Ulmus americana), which both occur in the Preserve, are very similar, overlapping in their characteristics and preferred habitats.
The leaves of both elms have especially noticeable "drip-tips" (these enable leaves to shed water more quickly). The leaf’s base is asymmetrical, and its border is doubly serrate — that is, the border has teeth, and the teeth have teeth. The Slippery Elm’s leaves are rough to the touch on top and have wooly hairs on the underside.
Photos by Peter Dziuk
The flowers are small and grow in tight clusters along a branch, forming in early spring before the leaves appear.
Both Elm species’ fruit is a small papery structure called a samara, dispersed by wind. The Slippery Elm’s samara, shown here, is round, 1⁄2 to 3⁄4 inch across, and typically has fuzz on the front and back surfaces, especially over the seed in the center. (The American Elm’s samara is elongated and deeply notched; it is smooth and hairless on the front and back surfaces but has fine hairs all around the margin.)
The flowers are small and grow in tight clusters along a branch, forming in early spring before the leaves appear.
Both Elm species’ fruit is a small papery structure called a samara, dispersed by wind. The Slippery Elm’s samara, shown here, is round, 1⁄2 to 3⁄4 inch across, and typically has fuzz on the front and back surfaces, especially over the seed in the center. (The American Elm’s samara is elongated and deeply notched; it is smooth and hairless on the front and back surfaces but has fine hairs all around the margin.)
Photos: flowers by Peter Dziuk, fruit and bark by David Rosher
The Slippery Elm’s bark is brown to reddish, developing deep, irregular furrows with age.
The Slippery Elm’s bark is brown to reddish, developing deep, irregular furrows with age.
On mature trees with thick bark, here’s a way to tell for sure if it’s a Slippery or an American Elm: break off a small flake of bark, and look at it edgewise. If you see alternating pale and dark bands, it’s an American Elm for sure; in a Slippery Elm, all the layers are a plain dark reddish brown.
More photos and ID tips: VA Tech dendrology, Minnesota wildflowers
Slippery Elm grows on medium-moist to moist soils of slopes and bottomlands, and in drier sites on calcareous soils, formed from limestone or dolostone. In
the Preserve, most specimens are in the bottomlands.
Interesting Facts:
Slippery Elm grows on medium-moist to moist soils of slopes and bottomlands, and in drier sites on calcareous soils, formed from limestone or dolostone. In
the Preserve, most specimens are in the bottomlands.
Interesting Facts:
- The tree’s common name is from its gelatinous or "slippery" inner bark.
- Slippery Elm is susceptible to Dutch elm disease, which famously killed so many American Elms lining streets in towns and cities across the country starting around 1930. The disease is caused by a fungus, which is carried by flying beetles and also passed from tree to tree via their roots. Wild-growing Elms in the Preserve and other forests, because of their low-level presence among other trees, fare better than urban elms.