Slippery elm (Ulmus rubra): what the agencies record

This page reports what US federal publications say about one tree. It does not identify trees from descriptions or photos and does not say what should be done with any tree. The family overview, tree species in the agency records, explains the sources and holds the comparison table.

At a glance

Item	What the source records
Scientific name	Ulmus rubra Muhl. in USDA PLANTS, elm family
Other names	Red elm, gray elm and soft elm (Silvics)
Native status, USDA PLANTS	Native in Canada and the lower 48 states
Size and age, Silvics	On average sites 18.3 to 21.3 m (60 to 70 ft) tall and 61 to 91 cm (24 to 36 in) in diameter; on the best sites 41.1 m (135 ft) tall and 122 cm (48 in); the largest living specimen the handbook lists, in Perry County, Pennsylvania, is 27.4 m (90 ft) tall and 193 cm (76 in) in diameter; it may live to be 200 years old
Shade, Silvics	Classed as tolerant of shade, much more tolerant than quaking aspen and slightly less tolerant than sugar maple; most often part of the subcanopy
Seed, Silvics	Large crops every 2 to 4 years, beginning after age 15; seeds ripen from April to June and are dispersed by wind
Green weight of the wood, NRS-38	53 lb per cubic foot, without bark

Native range and sites

The Silvics of North America handbook (Agriculture Handbook 654, volume 2, 1990) says slippery elm, identified by its slippery inner bark, extends from southwestern Maine west to New York, extreme southern Quebec, southern Ontario, northern Michigan, central Minnesota and eastern North Dakota; south to eastern South Dakota, central Nebraska, southwestern Oklahoma and central Texas; then east to northwestern Florida and Georgia. It calls the tree uncommon in the part of its range south to Kentucky and most abundant in the southern Lake States and the corn belt of the Midwest.

The handbook says slippery elm grows best on moist, rich soils of lower slopes, streambanks, river terraces and bottom land, but is often found on much drier sites, particularly limestone ones. It can persist on poorly drained soils flooded for 2 or 3 months but does not reproduce or grow well if flooding is frequent or prolonged. Its associates include more than 60 deciduous tree species, and it is named as a frequent invader of tree plantings on surface-mined land.

Flowers and growth

Silvics says slippery elm has inconspicuous, perfect flowers that appear in spring before the leaves, from February to May depending on weather and location. Seeds are larger than those of many native elms and the species sprouts readily from stumps. The handbook calls juvenile growth rapid in the open or under light shade, slightly exceeding American elm, with trees 2.5 cm (1 in) in diameter being 7 to 18 years old in southeastern Minnesota depending on competition. Rootstocks of slippery elm are often used to propagate hybrid elms.

Wood

Silvics says slippery elm is not an important lumber tree: the hard, strong wood is considered inferior to American elm, though the two are often mixed and sold together as soft elm, and it is used commercially for furniture, paneling and containers. The Wood Handbook (FPL-GTR-282, 2021) puts American and slippery elm in the soft elm class, moderately heavy, with high shock resistance, moderately hard and stiff, and says elm has excellent bending qualities. The wider elm context is on the American elm page. Table 5-3b has a separate slippery elm row, shown below.

Wood Handbook Table 5-3b	Specific gravity	Modulus of rupture (lbf per square inch)	Side hardness (lbf)
Green	0.48	8,000	660
At 12% moisture content	0.53	13,000	860

The Wood Handbook states that specific gravity is based on oven-dry weight and the volume when green or at 12% moisture content. The green weight of the wood without bark is in the NRS-38 table, the same figure used in the log weight calculator.

Diseases, insects and damage the handbook names

Silvics (1990) says slippery elm has many of the same diseases as American elm, and that more than 125 insect species feed on trees in the elm genus, excluding those that feed only on American elm.

Dutch elm disease. The handbook says slippery elm is attacked and killed by it. The smaller European elm bark beetle is named as the primary vector in the United States, with native elm bark beetles also able to transmit it. See Dutch elm disease and the European elm bark beetle.
Elm yellows (elm phloem necrosis). A mycoplasma-like organism that the handbook says kills slippery elm through much of its range; the whitebanded elm leafhopper is named as the principal vector. See elm yellows. The handbook says these two diseases are so virulent and widespread that slippery elm seldom reaches commercial size and volume as a forest tree, and that it is being replaced as a street tree in many localities.
Other diseases. A dieback caused by Dothiorella ulmi, widespread from New England to Mississippi and often confused with Dutch elm disease; a leaf spot (Gnomonia ulmea); brown wood rot, white flaky rot and a butt rot; slime flux and wetwood (see slime flux and wetwood); and nectria canker. In a Davidson County, Tennessee, survey, mistletoe (see mistletoe on trees) was more numerous on slippery elm than on any other species except American elm and white ash.
Defoliators and sucking insects. The elm leaf beetle, the larger elm leaf beetle (which especially favors slippery elm), elm calligrapha, cankerworms, the whitemarked tussock moth, the elm sawfly, aphids and scales. The spongy moth, listed by its older name, gypsy moth, feeds on slippery elm leaves but is not a preferred host; see the spongy moth page.
Other damage. Bark stripping by deer, more frequent on slippery elm than on other species in mixed hardwood stands, and crown breakage after severe ice storms in Wisconsin.

The guide on reporting a pest in the United States and the Canada reporting page give the offices that take sightings of regulated pests. Who may apply pesticides is in pesticide licences by country.