Black Locust
Robinia pseudoacacia
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Black locust is planted in all of the lower 48 states, and has escaped cultivation in many locations. It has been readily naturalized in some regions, but is considered invasive in others. It is native to the US, but its exact original range isn't accurately known. It is thought that the native range includes two main regions--an eastern region centered in the Appalachian Mountains and a western region including the Ozark plateau and Ouachita Mountains. It is widely tolerant of soil conditions.
Fruit: A 5-10 cm long, dark brown legume. Each pod contains 4-8 seeds. They display from July to November, and often persist through winter.
Flowers: A white, fragrant, pea-shaped flower arranged in racemes. The racemes can grow to 8 inches long and they bloom April-June.
Uses: Wood is hard and naturally rot resistant, making it a good choice for fenceposts and rails.
Ethnobotany: The wood was used by Native Americans and American colonists for the same reasons it's currently used. It was used for posts, bows, and ships.
Importance to wildlife: Black locust is a larval host for several butterflies, including Clouded Sulphur, Zarucco Duskywing, and Silver-Spotted Skipper. The buds and catkins are eaten by birds. Bees are attracted to the flowers and rabbits depend on the sprouts and seeds in the winter.
The full black locust tree. Black locust is a deciduous tree that grows 30-50 feet tall.
The bark of a black locust. As it ages, the furrows will deepen and the bark will become reddish brown to black.
The twig of a black locust. Notice the striped pattern. Black locust twigs are especially brittle.
The leaf arrangement of a black locust. Leaves are pinnately compound with 7-19 leaflets.
A single leaflet on a black locust. Leaflets are 2-6 cm long, bluish green and glabrous above, and much paler and glabrous beneath except for hairs along the midrib. Leaves turn gold/yellow in the fall.
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