If you want a plum tree (Prunus spp.) for a garden of native plants, you'll have to put up with prickles, as wild plums have thorny branches -- including the one you'll most likely encounter, the American wild plum (Prunus americana).
American Wild Plum
American wild plum is widespread throughout the United States where it grows in USDA zones 3b through 8. It grows from 15 to 18 feet high and 12 to 18 feet wide, with thorny branches growing from multiple trunks or clumps of stems. It shows white flowers in spring and yields 1/2-inch-wide plums that ripen from red to yellow. Birds like the plums, and they can be made into jellies.
Chickasaw plum (Prunus augustifolia), sometimes called sand plum, sandhill plum or mountain cherry, grows from 3 to 10 feet tall forming extensive thorny thickets in the wild. It grows with multiple stems with branches that have reddish brown bark, and it yields 1/4- to 1/2-inch-wide yellow, orange or red plums with thin skin. The plums can be bitter, although they are sometimes eaten fresh or used to make jam, jelly and wine. The Chickasaw plum is widespread in sandy prairies and will grow in USDA zones 6a through 9b.
The flatwoods plum (Prunus umbellata) grows 12 to 20 high and just as wide, yielding dry, hard, purple plums among its droopy, thorny branches. The 1/2 to 1-inch-wide plums, much loved by birds, are tart to sweet. It bears showy creamy white to gray flowers in spring. Found naturally in the southwest United States, it will grow in USDA zones 8a through 9b.
Canada plum (Prunus nigra), also called Princess Kay plum, is a wild plum that grows 15 to 20 feet high and 12 to 15 feet wide in the southern parts of Eastern Canadian provinces and in the mountains south along the East Coast to Georgia. Growing in USDA zones 3 through 9, it has thorns on its branches that grow to about 2 inches long. It is grown primarily for its fragrant white flowers with double rows of petals that turn pink as they mature in the spring. Its yield of plums is negligible, although they can be eaten fresh or made into wine, jellies and jams.
The endangered scrub plum (Prunus geniculate) is native to areas of central Florida within USDA zones 9a and 9b. It has a gnarled trunk with zig-zagging branches with thorns at their tips. It yields bitter, reddish purple plums about an inch long. As of 2008, there were less than 100 of these trees left.