Ulmus rubra (Red Elm)
|Also known as:||Slippery Elm|
|Life cycle:||perennial woody|
|Habitat:||part shade, sun; hardwood forest, floodplains, stream banks|
|Bloom season:||March - May|
|Plant height:||60 to 100 feet|
|Wetland Indicator Status:||GP: FACU MW: FAC NCNE: FAC|
|MN county distribution (click map to enlarge):|
|National distribution (click map to enlarge):|
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Dense, round clusters ¾ to 1 inch across from lateral buds on 1-year-old branches, each with 10 to 20 flowers and appearing before leaves emerge. Flowers have no petals, the green to reddish, cone-shaped calyx is hairy, only about 1/8 inch wide with 5 to 8 rounded, papery lobes. In the center is a 2-parted, pinkish-red, feathery style and 5 to 8 erect, white stamens that are at least twice as long as the calyx, the stamen tips initially reddish-purple turning purplish black. Flower stalks are hairy and less than 1/8 inch long.
Leaves and bark:
Leaves are simple and alternate, oval-elliptic to obovate (widest above the middle), 3½ to 7 inches long, 2 to 4 inches wide, abruptly tapered to a pointed tip, rounded and asymmetrical at the base, on a short, hairy stalk. Edges are double-toothed with roughly half the veins forking towards the tip (easily seen on the underside). The upper surface is medium to dark green with stiff, short hairs making it rough to the touch, the lower surface light green with similar stiff hairs though not as rough to the touch, and dense tufts of hairs in vein axils.
Young twigs are hairy and initially green, turning gray to gray-brown. Buds are up to ¼ inch long, elliptic, hairy at the tip, with hairy, dark brown to blackish scales; flower buds are larger, round, densely covered in rusty-colored hairs.
Red elm is a large forest tree, restricted mostly to the southern 2/3s of Minnesota, typically in more upland sites. The inner bark is sticky and a bit slimy, hence the other common name, Slippery Elm. While never as common as American Elm (Ulmus americana), its populations were also devastated by Dutch Elm Disease and today it is somewhat scarce. It certainly does not have the regeneration of American Elm and, while very similar, it can be distinguished by its round, button-like clusters of nearly stalkless flowers, leaf veins that frequently fork towards their tips and short, soft hairs on the fruit surfaces but not around the edges. The flower clusters much resemble those of the non-native Siberian Elm (Ulmus pumila), which are about half the size of Red Elm and have creamy yellowish styles, not red. These two species do hybridize, resulting in trees with intermediate characteristics.
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Where to buy native seed and plants ↓
- Red Elm tree
- Red Elm tree
- trunk of midsize tree
- twig and buds
- more leaves
- leaf veins forked at the tip
- flowering branch
Photos courtesty Peter M. Dziuk taken in Anoka, Fillmore and Hennepin counties.
Have you seen this plant in Minnesota, or have any other comments about it?