Black locust (Robinia pseudoacacia)
Appearance: Fast growing tree up to 75' in height with deeply furrowed with flat-topped ridges. Seedlings and root sprouts have long thorns and grow rapidly.
Leaves: Alternate, pinnately compound (leaflets on both sides of a common stalk) with 7- 21 elliptic, untoothed leaflets, with one leaflet at the tip. A pair of short, sharp thorns sit at the base of each leaf where it is attached to the twig.
Flowers: Fragrant, drooping white flowers arranged in elongated clusters appear in late May and June.
Seeds: Seed pods are smooth, 2 - 4" long; they mature in September and persist through winter.
Roots: Extensive fibrous root system. Spreads vegetatively through root suckering and runners.
- Wisconsin DNR Fact Sheet
- MISIN black locust identification training module
- Woody vegetation control (U of MN)
- Plant Conservation Alliance Fact Sheet