Black Locust (Robinia pseudoacacia)
Key Identification Features
Description
Black locust is a medium to large tree in the pea family (Fabaceae). Mature trees may reach 100 feet in height and 47 inches in diameter. The bark of mature trees is thick with deep furrows. Twigs are armed with large sharp spines. Its leaves are pinnately compound, 7 - 18 inches long, with 3 to 9 pairs of round leaflets and one terminal leaflet. Black locust flowers from late spring to early summer, producing 4 - 8 inch long clusters of white flowers. Its fruits are dark brown dry pods which split open to release seeds. Many parts of this tree are toxic to humans and other mammals if ingested, and can potentially be fatal.
Native Range
Native to the southeast U.S. and the Appalachian Mountains, black locust has been widely cultivated for its durable rot resistant wood, which is often used for building outside structures such as fences. It is also a commonly used species for honey production. It can now be found in all of the lower 48 states, and is considered invasive in a number of them.
Habitat and Dispersion
Black locust requires open areas with full sun exposure to become established. They can often be found along roadsides, in fields, old pastures, and in open disturbed areas. When found growing in a forest, it is likely that they became established before other trees grew around them. Their large root system allows them to reproduce rapidly through clonal sprouting, making them a threat to open areas which they can quickly shade out and dominate, lowering an area's biodiversity.
Best Management Practices
Due to its ability to resprout, cutting and mowing are ineffective for long term control. Systemic herbicides should be applied to cut stumps in order to prevent clones from appearing, but this still may not prevent future resprouting.