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Robinia pseudoacacia

LHPrism Status 
Tier 4 - Widespread
Species Type 
  • Terrestrial Plants
  • Tree
Deciduous Forest
Impacts of this species 

 Vegetative regeneration is vital in this plant's establishment, spread and persistence in non-native locations, giving it the ability to replace native vegetation. Developing black locust thickets can prevent other plants from establishing and may disrupt historical successional trajectories. In mixed-hardwood forests, these trees have been seen to contribute to elevated stream nitrate concentrations.  Because of its nitrogen fixing abilities, black locust may also alter local soil characteristics, in turn disrupting biological activity in soil and preventing certain native plants from growing. Black locust canopies may block sunlight from reaching seedlings of other plants, such as native oaks, ultimately lowering species diversity. Seeds may remain viable in soil for more than 10 years, and are oportunistic in growth, giving them the ability to thrive through non-ideal conditions.


Robinia pseudoacacai is native to parts of North America, including the Sourthern Appalachians, the Ozarks, and other portions of the Midsouth. It has spread from its native regions and has become invasive in other parts of the country. It was planted widely as being a hardy street tree and for erosion control. It is now widespread throughout the Lower Hudson Region

Black locust are leguminous, deciduous trees that grow up to 80 ft. in height. In forest settings, they'll grow upright, but in more open areas will develop an open growth form. Young saplings have smooth, green bark, but as they get older get deep, furrowed,shaggy, dark bark with flat-topped ridges. The leaves of the tree are alternate and pinnately compound, with one leaf per node. 7-21 thin, elliptical dark green leaflets make up the leaves. The leaf margin has no teeth or lobes. The flowers are pea-like, fragrant, white-yellow, born in large, drooping racemes. Seed pods are smooth, shiny, narrow, flat, between 5-10 cm long, and contain 4 to 8 seeds.

This tree is an early successional plant, preferring full sun, well drained soils, and little competition. It invades dry and sand prairies, floodplains, oak savannahs, and upland forest edges. It is found prominently in in disturbed areas including old fields, degraded woods, and roadsides. 

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