June Plant of the Month – Mexican Plum (Prunus mexicana)

By Sue Abernathy

Mexican Plum (Prunus mexicana), a member of the Rosaceae (Rose) Family, is also known as Big Tree Plum, Inch Plum, and Wild Plum.  It is a beautiful single-trunked, flowering, deciduous tree with bark that eventually gets dark and striated, peeling off in patches on old trunks.  It has an irregular branching structure with somewhat thorny branches.  Early in the spring, it is covered with clusters of two to six fragrant white flowers before the leaves appear.  The flowers are reminiscent of Crabapples (Malus spp.) when in bloom and provide nectar for bees. The dark red to purple plums ripen in summer to early fall.  The plums are edible and can be used in preserves, but are most valued as food for birds and mammals. The leaves are 2 to 4 inches in length, smooth and dark green.  At times they are folded over and look like they are drooping from lack of water.  Fall leaf color ranges from yellow to a beautiful orange.

Mexican plum is relatively drought tolerant, soil pH adaptable, and suited to full to part sun, but requires good soil drainage.  It is often found in its native Texas habitat (mostly in northeast and north central Texas) along woodland edges, river bottoms, open woods, fencerows and well-drained prairies.  Because it grows singly and does not sucker or form thickets as do many other native plums, its rootstock is widely used for grafting.  Mexican plum grows in a rounded shape to a height of 15–30 feet and a spread of 20–25 feet at maturity and is hardy to USDA zone 6.  It grows at a slow rate, with height increases of less than 12 inches per year.

Mexican plum is most often planted as an ornamental or understory tree.  Its iridescent white flowers are of prime ornamental value, while the fruit, bark, and fall color are secondary assets.  It is a good alternative for Japanese Maple and Crabapple trees for the residential landscape.  These trees can be seen growing at Hagerman National Wildlife Refuge in the landscaped area at the Visitor Center, in the Butterfly Garden, and in the wild.  Occasionally, a few insects chew on the leaves but the tree does not have major pest problems and is tolerant of cotton root rot which devastates many members of the family Rosaceae.  It is rather difficult to transplant from the wild except for very small trees, but is widely cultivated and readily available in the nursery trade.

Sources:

Aggie Horticulture at http://aggie-horticulture.tamu.edu

Lady Bird Johnson Wildflower Center at http://www.wildflower.org

National Arbor Day Foundation at https://www.arborday.org

Photo credits – Sue Abernathy