Ground plum is a many-stemmed, bushy perennial. Flowers in tight racemes, nearly 1 inch long, cream-colored with lilac-blue tips of the keel petals; also purple to bluish purple or pinkish purple or greenish yellow to white. Blooms March–May. Leaves compound, with many opposite, oblanceolate leaflets. Fruit nearly ball-shaped with a central ridge, with a sharp, beaklike point; smooth, about ¾ inch wide.
Similar species: Four species of Astragalus are recorded for Missouri. Rattleweed (A. canadensis) blooms May–August and grows to 4 feet tall. Its long clusters of flowers are greenish white to cream-colored. The compound leaves have many opposite leaflets that get shorter toward the tip and are oblong to elliptical. It grows statewide, usually in open, wet lowlands.