Common Name: Black Locust
Scientific Name: Robinia pseudoacacia L.
Efforts must be made to prevent seed maturation and dispersal of plants into new areas. Additionally, no transportation, propagation, or sale of these plants is allowed. Failure to comply may result in enforcement action by the county or local municipality. Minnesota Noxious Weed Law.
Black locust is native to North America, but not to Minnesota or the Upper Midwest. It is native to the Appalachian region and the Ozarks, where it is also considered a weed. It has been widely planted as an ornamental, for land reclamation, and for erosion control. It is also a major honey-producing plant in the eastern U.S. Black locust is spreading into new areas and is now a threat to other states which are outside of the historical range.
The native habitats of black locust are temperate, moist to wet forests and wooded slopes. It will invade disturbed sites such as old fields, cleared areas, and degraded woods and thickets.
Black locust spreads mainly through intentional human plantings and disturbance. The seeds are long-lived, remaining viable in the soil for up to 10 years, although the seeds generally have poor germination rates. Seed can spread moderate distances by wind, gravity, and possibly birds. The seedlings can sprout and grow fast, enabling this species to colonize disturbed sites very quickly. Once established on a site, the trees reproduce vigorously by root suckering and stump sprouting to form clonal groves linked by a shared root system.
Black locust occurs throughout the Eastern U.S., from the East Coast to the Great Plains states. In Minnesota, it has been reported in about half of the 87 counties.
Black locust can outcompete and exclude other tree species and native prairie and savanna plants. It can form a monoculture on disturbed sites.
Being a legume, it has the ability to fix nitrogen in the soil and as a result, it may alter local soil characteristics. By increasing soil nitrogen, it can create a favorable habitat for other colonizing nonnative species.
Black locust leaves, stem, bark, and seeds contain robin, a toxic compound. Ingestion results in gastrointestinal and neurological dysfunctions which are particularly acute in horses and can be fatal.