Ulmus rubra is a medium-sized deciduous tree with a spreading head of branches,[4] commonly growing to 12–19 metres (39–62 feet), very occasionally over 30 m (98 ft) in height.

The reddish-brown fruit is an oval winged samara, orbicular to obovate, slightly notched at the top, 12–18 mm (15⁄32–23⁄32 in) long, the single, central seed coated with red-brown hairs, naked elsewhere.

[7] U. rubra is chiefly distinguished from American elm by its downy twigs, chestnut brown or reddish hairy buds, and slimy red inner bark.

The tree was first named as part of Ulmus americana in 1753,[8] but identified as a separate species, U. rubra, in 1793 by Pennsylvania botanist Gotthilf Muhlenberg.

The slightly later name U. fulva, published by French botanist André Michaux in 1803,[9] is still widely used in information related to dietary supplements and alternative medicine.

In the central United States, native U. rubra hybridizes in the wild with the Siberian elm (U. pumila),[13][14] which was introduced in the early 20th century and has spread widely since, prompting conservation concerns for the genetic integrity of the former species.

[16] Introduced to Europe and Australasia, it has never thrived in the UK; Elwes & Henry knew of not one good specimen,[7] and the last tree planted at Kew attained a height of only 12 m (39 ft) in 60 years.

In Germany, the tree formed part of a complex hybrid raised by the Eisele nursery in Darmstadt, provisionally named 'Eisele H1'; patent pending (2020).

[31] Though now outmoded, slippery elm tablets were chewed by spitball pitchers to enhance the effectiveness of the saliva applied to make the pitched baseball curve.

[citation needed] Once cured, the wood is also excellent for starting fires with the bow-drill method, as it grinds into a very fine flammable powder under friction.