Black Locust
Robinia pseudoacacia · Deciduous, Broadleaf, Hardwood
Plant Family
Fabaceae
Tree Category
Shade Tree, Forest Tree, Flowering Tree
Variety / Cultivar
Standard species
Hardiness Zones
USDA Zones 4 through 8
About This Tree
A fast-growing, medium-sized tree with an irregular, upright form and translucent foliage. It features pendulous racemes of fragrant white flowers and flat, brown seed pods. Older specimens develop a deeply furrowed, craggy appearance.
Leaf Characteristics
Pinnately compound leaves, 6-14 inches long with 7-21 oval leaflets. Leaflets are bluish-green, turning yellow in autumn. Arrangement is alternate.
Bark Characteristics
Dark gray to brown, deeply furrowed into thick, ropy ridges that often form a diamond-like pattern or cross over one another.
Growing Information
Origin Region
Native to the Appalachian Mountains and Ozark Plateau; widely naturalized throughout North America and Europe
Growing Season
Leafs out in late spring; flowers in late spring to early summer; seeds mature in autumn; deciduous dormancy in winter
Sunlight & Water Needs
Full sun is required; high drought tolerance once established; adaptable to various soil types including poor, rocky, or sandy soils.
Mature Size
Reaches 30-50 feet in height with a 20-35 foot spread; fast growth rate; typical lifespan is 60-90 years.
Special Characteristics
Known for nitrogen-fixing capabilities; extremely rot-resistant timber used for fence posts and ship building; highly fragrant flowers; considered invasive in some regions outside its native range.
Wildlife & Ecology
Flowers provide high-quality nectar for honeybees and butterflies; seeds are eaten by bobwhite quail and other game birds; provides nesting cavities for woodpeckers in older, decaying wood.