Black Locust (Robinia pseudoacacia)

Form

A medium sized tree, 30 to 50 feet high; sometimes larger. Open grown specimens usually branch low, forming a narrow, open crown. Twigs and branchlets carry strong, sharp spines which occur in pairs with a leaf-scar between them.

Bark

Brown with yellow or orange inner bark; heavily furrowed, forming an interlacing pattern of fibrous ridges, rope-like.

Leaf

Alternate, compound; consisting of from 7 to 19 oblong, thin leaflets.

Fruit

A legume; 3 to 5 inch long pod containing 4 to 8 small, hard seeds which ripen late in the fall and persist through the winter on the tree.

Range

Not native to the state, but has been planted extensively. In some places has escaped from cultivation, as it grows on a wide variety of soils.

Wood

Yellow in color, close grained, very heavy and hard; strong and very durable in contact with the soil. The wood is potentially valuable, but rarely obtains log size due to attacks of the locust borer. Use is therefore limited to fence posts and firewood.

Notes

Originally planted for soil erosion control purposes, for which it is well suited. Fragrant, white flowers in the spring make it very attractive. Is generally considered a weed because it spreads prolifically by suckering.