Black Walnut
Juglans nigra · Deciduous Broadleaf / Hardwood
Plant Family
Juglandaceae
Tree Category
Nut Tree / Shade Tree / Timber Tree
Variety / Cultivar
Native species (Common Black Walnut)
Hardiness Zones
USDA Zones 4 through 9; adaptable to various climates but thrives in temperate woodland environments.
About This Tree
Large, stately tree with an open, spreading, rounded crown. Known for its dark, deeply furrowed bark and high-value dark wood. It grows at a moderate rate and reaches impressive sizes in fertile, bottomland soils.
Leaf Characteristics
Pinnately compound, 12 to 24 inches long with 15 to 23 leaflets. Leaflets are ovate-lanceolate with serrated margins; yellow-green in summer, turning clear yellow in autumn.
Bark Characteristics
Greyish-brown to black, developing deep, diamond-shaped furrows and thick, rough ridges as it matures. The inner bark turns dark brown when exposed to air.
Growing Information
Origin Region
Native to Eastern and Central North America, from Southern Ontario to Texas and Georgia.
Growing Season
Leafs out late in spring; flowers appear in late spring (April to May); nuts ripen in autumn; enters dormancy early by dropping leaves in late summer or early fall.
Sunlight & Water Needs
Requires full sun; prefers moist, well-drained, deep, rich loamy soils. Moderate drought tolerance once established but prefers consistent moisture.
Mature Size
Reaches 70 to 100 feet in height with a similar spread. Can live up to 150-250 years. Trunk diameter typically 2 to 4 feet.
Special Characteristics
Produces 'juglone', a chemical that inhibits the growth of certain other plants (allelopathy); produces highly prized dark timber and edible nuts; leaves and husks have strong citrusy-pungent odor.
Wildlife & Ecology
Provides essential food for squirrels and other rodents who cache the nuts; serves as a host plant for the Luna Moth; provides nesting sites for large birds; husk nut residue can be toxic to some organisms.