Black Locust
Black Locust, Robinia pseudoacacia, photo by LH PRISM
Additional Images
Common Name: Black locust
Scientific Name: Robinia pseudoacacia
Origin: Appalachian Mountains (Southeast U.S.)
Description
Black locust is a fast growing tree that can grow to be 40-100 ft. tall. It has alternate, compound leaves with 7-21 oval-shaped leaflets per leaf. Pairs of thorns are found at the base of each leaf. Throughout May and June it produces clonal, drooping clusters of fragrant white flowers. In September, the black locust fruit mature into 2-4″ long seed pods, which will remain on the tree into winter.
Habitat
Black locust is an early-successional plant, preferring full sun and rocky, or sandy, soils. As a legume, this tree can thrive and grow rapidly in nitrogen-deficient soils. Black locust are most often found in abandoned fields, prairies, woodlands, stream banks and roadsides.
Threat
Black locusts threaten prairies, savannahs and upland forests. They have an extensive root system that allows them to reproduce clonally, sprouting many clones in one area. As they grow, they’ll form islands of dense canopy which shade out any plants below them.
Management
Cutting and mowing are ineffective methods for killing black locust. Systemic herbicides should be applied to the cut stumps of every black locust stump in a clone. Treated stumps may appear to be killed but re-sprout years after treatment, so follow-up monitoring and treatments are required for several years.
Regional Distribution
Common
WNY PRISM Priority
Tier 4 – Local Control
Invasive Species Priorities – Tier Chart
Black Locust is a regulated species in New York State – for more information on Prohibited and Regulated Species, visit http://www.dec.ny.gov/animals/99141.html.
Native Alternatives
Bitternut hickory (Carya cordiformis)
Shagbark hickory (Carya ovata)
Tulip tree (Liriodendron tulipifera)
This map shows confirmed observations (green points) submitted to the NYS Invasive Species Database. Absence of data does not necessarily mean absence of the species at that site, but that it has not been reported there. For more information, please visit iMapInvasives.
