Wild plum is a shrub that propagates itself by root sprouts to form thickets, or it can be a small tree with spreading, more or less hanging, branches.
Leaves are alternate, simple, 2½–4 inches long, 1½–2 inches wide, broadest at or below the middle; margin sharply toothed; upper surface dark green, lower surface paler and net-veined.
Bark is dark brown to reddish, breaking into thin, long, scaly plates, pores horizontal and prominent.
Twigs are slender, smooth, green to orange to reddish-brown; lateral branches spurlike or sometimes thorny; pores circular, raised, minute buds smooth (without hairs).
Flowers April–May, in clusters of 2–5, stalks ¼–¾ inch long, smooth; flowers ¾–1¼ inches broad, white, fragrant; petals 5, broadest at the middle, rounded at the tip, and narrow at the base; stamens about 20.
Fruits July–September, in clusters with 1–5 fruits; fruit usually ¾–1 inch long, globe-shaped, red or sometimes yellow, conspicuously marked with pale dots; skin tough; flesh yellow and juicy, varying in flavor.
Similar species: Several other small trees bloom in spring with white, five-petaled flowers. Serviceberry has petals that are bright white, strap-shaped, wavy, with a space between them (not rounded and close together). The invasive Callery (or Bradford) pear has white petals that are rounded and close together (they touch/overlap at their bases); its flower stamens are not longer than the petals; and the flowers are unpleasant-smelling. Apple and crabapple flowers have a slightly pink hue.