Plant Characteristics:
- Tree: 30 to 70 ft tall; 1 to 2 ft wide
- Bark: gray or light brown, thick with irregular furrows and grooves; ropey
- Twigs: brown to reddish brown with lighter pores (lenticels); paired spines at each node
- Buds: are not visible and beneath leaf scars
- Leaves: deciduous, alternate, pinnately compound about 20-35 cm long; with 9-19 stalked oval or ovate leaflets; leaflet margins entire dark green above and paler beneath
- Fall Foliage: yellow
- Flowers: stems of flowers (racemes) about 7 to 20 cm long hang down; fragrant, creamy, white flowers are about an inch long and pea shaped with a banner petal at the top, wings to the sides, and a keel at the bottom containing the male and female reproductive parts
- Fruit type: pod, brown, flat, 5-10 cm long, containing 4- 7 seeds (attached); splits into two lengthwise, each carried by the wind scattering the seeds
Additional Details:
- American Indians chewed the root bark to induce vomiting or held bark in their mouth to allay toothaches.
- All parts of the tree are toxic.
- Recognized by pollination ecologists as attracting large numbers of native bees.
- The wood is heavy, hard and strong, and durable when in contact with the ground. It is used for erosion control, posts, railroad ties, etc.
- This tree is a nectar source and attracts butterflies and birds.
The black locust bark is often eaten by cottontail rabbits and deer in the winter months. Birds that eat the seeds include bobwhite quail and other game birds.
The Locust Borer (Megacyllene robiniae) is the most serious threat to trees by damaging and weakening trunks. The Locust Leafminer (Odontota dorsalis) causes premature browning and death of foliage in late summer.
The shelf fungus most commonly found on black locust trees is the Cracked Cap Polypore (Phellinus robiniae, formerly Fulvifomes robiniae).
Black locust is a nitrogen fixer and is good at reclaiming mine sites and other disturbed lands.
References:
Brown, R. and M. Brown. 1972. Woody Plants of Maryland. Port City Press, Baltimore, MD.
Foster, S. and J. Duke. 1990. A field guide to medicinal plants of Eastern and Central North America. Houghton Mifflin Company, Boston, MA.
Grimm, W. C. and J. Kartesz. 2002. The Illustrated Book of Trees. Stackpole Books. Mechanicsburg, PA.
Harris, J. and M. Woolf Harris. 1994. Plant Identification Terminology: An illustrated Glossary. Spring Lake Publishing, Spring Lake, UT.
Peterson, L. 1977. A field guide to edible wild plants of Eastern and Central North America. Houghton Mifflin Company, Boston, MA.
Virginia Department of Forestry. 2022. Common Native Trees of Virginia – Tree Identification Guide.
The Wildflower Center Staff. 2023. Plant Database. Lady Bird Johnson Wildflower Center. The University of Texas at Austin.