Leaf:  Alternate, simple, in 2 rows; blades oval to elliptic, long-pointed at the tip, strongly asymmetrical at the base; 4 to 7 inches (10 to 18 cm) long, about half as wide; thick; coarsely doubly saw-toothed along the edges with many straight parallel side veins; the upper surface green to dark green and very rough to the touch, the lower surface smooth or hairy, sometimes densely covered with soft hairs beneath; leafstalks stout, hairy, up to 1/2 inch long; turning dull yellow in autumn.

Flower:  Numerous, in drooping clusters, appearing before the leaves unfold, greenish, hairy, small, 1/8" (3 mm) wide, short-stalked along twigs in early spring.

Fruit:  Circular, flat, winged fruits 1/2 to 3/4 inch (12 to 19 mm) in diameter, not hairy except over the seed; wing light green, broad, hairless, slightly notched at tip; each wing surrounding a single seed; maturing in spring.

Twig:  Rather stout, reddish-brown, with short, gray hairs; leaf scars alternate, half-round, each with 3 bundle traces; buds nearly round, up to 1/4 inch in diameter, with rusty-colored hairs.

Bark:  Dark reddish-brown to gray, with shallow furrows; the inner bark becomes slippery when chewed.

Form:  Moderate tree up to 80 feet tall ; trunk diameter 2 to 4 feet ; crown broadly rounded or occasionally flat- topped with spreading branches.

Discussion

Slippery elm has heavy, strong wood traditionally used for shipbuilding, farm implements and fence posts.  Today the wood is used for furniture, paneling, and containers.

Slippery elm was used in many ways by different native American tribes.  These uses were passed on to European settlers.  The outer bark supplied material for covering the sides and roofs of winter dwellings.  The inner bark was boiled and used for its fibers in making bags, storage baskets, ropes, and cords.  The thick, slightly fragrant, edible, gluelike inner bark was dried and later moistened for use alone or mixed with other plant products for multiple medicinal uses:  treating infected and swollen glands, soothing sore eyes, clearing up skin sores, and so on.  The inner bark was boiled and made into a tea to treat sore throats and to act as a laxative.  Women used the tea to make childbirth easier.  Even today, slippery elm can be obtained from health food stores for the treatment of sore throats, coughs, and bronchial disorders, and to use as a laxative.

Slippery elm has thick foliage suitable for nesting sites.  Songbirds, game birds, and squirrels eat the seeds and buds.  Deer and rabbits browse on the twigs.

Slippery elm is susceptible to Dutch elm disease, but not to the extent that the disease affects American elm.  Slippery elm seeds grow readily in moist, rich soils, and can become a weed in unkempt shrub borders, hedges, fence-rows, and other open ground.  We have found both American elm and slippery elm in the oak/hickory forest of Macoupin County in south-central Illinois, mostly as understory trees alongside wild black cherry, sassafras, red mulberry, and eastern redbud.

The Latin species name refers to the large brown buds covered with rust-colored hairs.

Distinguishing Characteristics

The rough, sandpapery texture of the asymmetrical leaves distinguishes this elm from all others in the state.  Locally, we check for layering inside a bark fragment.  If the bark is layered reddish-brown alternating with cream, it's an American elm.  Without this distinctive layering, it's a slippery elm.

Distribution

Quebec across to North Dakota, south  to Texas, east to Florida.

Images

Click each small picture to see larger image.

September, 2002 SG	September, 2002 SG	September, 2002 SG
May, 2003 Reddish-brown  bark chip	May, 2003 Bark of smaller tree

Location

N 39.26845°     W -89.88916°                                                                          
East side of southern loop of the fitness trail, Loveless Park, South Locust Street, Carlinville, Macoupin County, IL.

Copyright

Photos © Brooke Crays and Stephanie Goesmann, Carlinville High School, linke@carlinvilleschools.net

References

Robert H. Mohlenbrock, Forest Trees of Illinois, 1996, Illinois Department of Natural Resources.

Herbert S. Zim and Alexander C. Martin,  Trees, 1956, Western Publishing Company, Inc.

Elbert L. Little, Field Guide to Trees:  Eastern Region, 1980, Alfred A. Knopf.

United States Department of Agriculture, Natural Resources Conservation Service, Plants Database
http://plants.usda.gov/cgi_bin/topics.cgi
    (Fill in scientific name search box "Ulmus rubra"; click Plant Guide PDF.)

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