Ground Plum (Milk Vetch)

Astragalus crassicarpus (formerly A. mexicanus)


Photo of ground plum, top of plant, showing flowers and several leaves.
Ground plum is a legume with feather-compound leaves, spikelike clusters of pea flowers, and plumlike, edible fruits.
Gordon T. Maupin
Other Common Name
Buffalo Pea; Groundplum Milkvetch

Fabaceae (beans, peas)


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.


Height: to about 20 inches.


Photo of ground plum plant showing several of its round plumlike legume fruits.
Ground Plum (Fruits)
Ground plum fruits are smooth balls with a central ridge and with a sharp, beaklike point; they are about ¾ inch wide.


Photo of ground plum flower cluster with some leaves.
Ground Plum (Flowers)
Ground plum’s short, spikelike clusters of pea flowers can be white, cream, yellow, pink, or violet.
Habitat and conservation

Grows in upland prairies, loess hill prairies, roadsides, embankments, fields, glades, ledges and tops of bluffs, openings of rich to dry upland forests, often on calcareous substrates.

image of Ground Plum Milk Vetch Buffalo Pea Distribution Map
Distribution in Missouri

Counties adjacent to and south of the Missouri River. Scattered widely, but apparently absent from the Mississippi Lowlands and uncommon in parts of the Glaciated Plains Division.

Human connections

The round, two-parted, cherrylike fruits are succulent and sweet when young and can be eaten raw or boiled. Native Americans and settlers ate them. Because there is a potential for loco poisoning (neurological damage that is not reversible), eating large quantities is not advised.

Ecosystem connections

Rodents gather, cache, and eat the fruits. Wild mammals tend to avoid eating plants in this genus, since they, like livestock, can be poisoned by the toxic alkaloids present in the plants. The condition is called locoism, for the dazed, frantic, uncoordinated, crazed behavior it causes.