black locust
Robinia pseudoacacia

Secondary Names:

Leaf Type: Deciduous
Texas Native:
Tree Description:

A medium-sized tree of farms and old homesteads, to 50 feet tall and a trunk to 2 feet in diameter.

Range/Site Description:

Native to the northeast and midwest U.S., this species is widely planted in East Texas and has escaped from cultivation in fencerows and unmaintained fields. Prefers deep, well-drained, moist soil for good growth, but tolerates dry sites.


Alternate, once-compound, 10" to 14" long, with 11 to19 leaflets, each one oval and 1" to 2" long. Leaves are slightly blue-green on top and pale beneath; the twigs are armed with a pair of sharp, strong spines 0.25" to 0.5" long at the base of each leaf.


Drooping clusters of pea-like flowers, 3" to 6" long, white or cream-colored, fragrant, appearing after the leaves in spring.


A flattened, papery pod, 3" to 5" long, containing 4 to 8 small hard seeds which ripen late in the fall; pod splits open during the winter, but seeds often remain attached to each half of the pod.


Thick, light brown, with deep furrows and interlaced ridges.


Wood is yellow, heavy, very hard, strong, and durable in contact with the soil. Its uses include fence posts, railroad ties, tree nails, and insulator pins for electric lines.

Similar Species:

Waterlocust (Gleditsia aquatica) occurs in bottomlands of East Texas and has single-seeded pods. New Mexico locust (Robinia neomexicana) is found in the Guadalupe Mountains of West Texas.

Interesting Facts:

Used as plantings in strip mine reclamation projects because the seedlings tolerate the highly acidic soils and its roots possess nitrogen-fixing nodules that improve the soil.

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