The American plum grows as a large shrub or small tree, reaching up to 15 feet (4.6 m). It is adapted to coarse- and medium-textured soils, but not to fine soils (silt or clay). The shrub is winter-hardy, but has little tolerance for shade, drought, or fire. Its growth is most active in spring and summer; it blooms in midspring. It propagates naturally by seed, expanding as a stand relatively slowly, due to its long time to maturity when grown from seed.
The roots are shallow, widely spread, and send up suckers. The numerous stems per plant become scaly with age. The tree has a broad crown. The branches are thorny. The leaves are alternately arranged, with an oval shape. The leaf length is usually 2–4 in (5.1–10.2 cm) long. The upper surface of the leaf is dark green; the underside is smooth and pale. The small white flowers with five petals occur singly or in clusters in the leaf axils. The globular fruits are about 1 in (2.5 cm) in diameter.