Robinia pseudoacacia L.

Black Locust; False Acacia

Tree

Perennial

Vascular

Black Locust is a native deciduous tree in the Bean family (Fabaceae). It is native to most of Alabama. Black Locust occurs in hardwood or mixed pine/hardwood forests, along fence rows, along forest edges, in cut-over woods, and around old farms and homesteads. It is a small to medium sized tree reaching heights of 30-50 feet. It often forms thickets from root suckers. The bark is gray in color with thick ridges and furrows. Twigs are zig-zag with paired stout woody spins at each leaf scar. Leaves are alternate, petiolate, odd pinnately compound with 7-19 leaflets. The leaflets are ovate to elliptic in outline, pubescent but becoming glabrous, with entire margins. The flowers are produced in drooping racemes from the axils of the leaves. The flowers are fragrant, papilionaceous, and white in color. The standard petal is marked with yellow. The fruit is a legume. Black Locust has been widely planted outside its native range and is considered a pest in some parts of the United States and other countries. It has very hard, rot resistant wood that has been used for fence posts, rails, barns, furniture, and flooring. It is also a very desirable firewood that burns at high temperatures with little smoke. Black Locust is also planted as a landscape tree. It is tolerant of drought and poor soils. Several cultivars are available including ones without spines, ones with pink flowers, and dwarf forms. It prefers full sun and a well-draining soil. The leaves of Black Locust are a larval food plant for Funereal Duskywing (Erynnis funeralis), Zarucco Duskywing (Erynnis zarucco), and Silver-spotted Skipper (Epargyreus clarus) butterflies.--A. Diamond

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Native

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