Virginia Tech Dendrology

black locust Fabaceae Robinia pseudoacacia L. Listen to the Latin play symbol: ROPS
Leaf: Alternate, pinnately compound, with 7 to 19 leaflets, 8 to 14 inches long. Leaflets are oval, one inch long, with entire margins. Leaves resemble sprigs of grapes; green above and paler below.
Flower: Perfect, showy and fragrant, white, 1 inch long and pea-like, borne in long (5 inches) hanging clusters, appear in mid to late spring.
Fruit: Flattened legume, light brown, 2 to 4 inches long; containing 4 to 8 kidney-shaped, smooth, red-brown seeds, ripen in the fall.
Twig: Zigzag, somewhat stout and angular, red-brown in color, numerous lighter lenticels. Paired spines at each leaf scar (often absent on older or slow growing twigs); buds are submerged beneath the leaf scar.
Bark: Gray or light brown, thick and fibrous, heavily ridged and furrowed, resembles a woven rope.
Form: A medium sized tree to 70 feet, with a relatively straight trunk and a crown of crooked branches. Often forms thickets by root suckering.
Looks like: bristly locust - New Mexican locust - honeylocust - pea tree
leaf flower fruit twig bark form1 map
Additional Range Information: Robinia pseudoacacia is native to North America. Range may be expanded by planting. See states reporting black locust.
More Information: Fall Color - Wood - Landowner Factsheet
External Links: USDAFS Silvics of North America - USDAFS Additional Silvics - USDA Plants Database - Horticulture Information - USDAFS Forest Products Lab
All material © 2017 Virginia Tech Dept. of Forest Resources and Environmental Conservation; Photos and text by: John Seiler, Edward Jensen, Alex Niemiera, and John Peterson