Corkwood is a small tree or shrub that commonly reproduces vegetatively, as new trunks begin as suckers and arise from the shallow roots, creating thickets of trees that are all genetic clones of the first one.
Leaves are alternate, simple, at the ends of twigs, 3–6 inches long, 1–3 inches wide, broadest in the middle; margin lacking teeth; upper surface dark olive to dull green; lower surface paler, with long, soft hairs.
Bark is gray to brown, ridges narrow, grooves shallow.
Wood is pale yellow, soft, close-grained, and lightweight.
Twigs are reddish-brown to gray, smooth, finely furrowed, pores numerous. The large flower buds that overwinter resemble small pinecones.
Flowering is in late winter to early spring. Male and female flowers are in catkins on separate trees; catkins flower before the leaves emerge.
Fruit is flattened brown; in clusters of 2–6, 3/4 inch long, 1/4 to 1/3 inch wide.