Prunus maritima, beach plum, is a deciduous shrub in the Rosaceae (rose family) native to coastal areas of the northeastern U.S., from Maine to Virginia. Its plums are edible, but are quite tart and acidic, so they are generally used for jams and jellies. This species is used for coastal stabilization, to slow the erosion of sand dunes; in natural settings, it is an important food source for coastal wildlife. Although native to coastal areas, it can grow inland, and is sometimes cultivated for its fruit; several horticultural varieties have been developed.

Beach plum typically grows to around 2 m (6 ft) tall and has straggling or prostrate lower branches, although when grown inland may develop tree, rather than shrub, form, and reach heights up to around 8 m (18 ft). Branches occasionally have spines. Leaves are oval to elliptical, usually serrate (with sharp teeth) or crenate (wavy-margined), 2.5 to 6.5 cm (1 to 2.5 in) long, usually pubescent (with short downy hair) on the underside. The 5-petalled white flowers are small, around 1 cm (less than 0.5 in) in diameter, and generally occur in clusters of two or three. Fruits are spherical to oval drupes, with firm, somewhat juicy flesh and a hard pit. Fruits range in color from red to purple (one horticultural variety is yellow), and are covered with a waxy bloom.

Two naturally occurring varieties grow along the Atlantic coast in the Northeastern U.S., and both are listed as endangered: var. maritima is recognized as an endangered species in Maine, Maryland, Pennsylvania; and var. gravesii is listed as endangered in Connecticut.

(Bailey et al. 1976, Everett 1981, Hedrick 1919, USDA 2002.)