Black Walnut
Juglans nigra · Deciduous, Broadleaf, Hardwood
Plant Family
Juglandaceae
Tree Category
Nut Tree, Forest Tree, Shade Tree, Timber Tree
Variety / Cultivar
Standard species
Hardiness Zones
USDA Hardiness Zones 4-9. Highly adaptable to temperate continental climates but sensitive to frost in very early spring.
About This Tree
A large, stately forest tree with a straight trunk and an open, rounded crown. Known for its dark, deeply furrowed bark and valuable timber. It grows at a moderate rate and develops a massive taproot, making it difficult to transplant once established.
Leaf Characteristics
Pinnately compound, 12-24 inches long with 15-23 leaflets. Leaflets are ovate-lanceolate with finely serrated margins. Foliage is green, turning a clear yellow in autumn before dropping early.
Bark Characteristics
Thick, dark brown to grayish-black bark, deeply furrowed into rough, diamond-shaped ridges. The inner bark of a fresh cut often shows a dark chocolate color.
Growing Information
Origin Region
Native to Eastern North America (Canada to Northern Florida, west to the Great Plains)
Growing Season
Leafs out in late spring (one of the last to leaf out); flowers in April-May; fruits ripen in autumn; enters dormancy in early Fall.
Sunlight & Water Needs
Full Sun (shade intolerant). Prefers deep, moist, well-drained loamy soils. Moderate water needs; once established, it has moderate drought tolerance.
Mature Size
Mature height of 70-100 feet with a similar spread. Growth rate is moderate. Long-lived, often reaching 150-250 years.
Special Characteristics
Produces 'juglone', an allelopathic chemical that can inhibit the growth of certain other plants (like tomatoes or pines) nearby. Highly prized for its dark, durable decorative heartwood used in fine furniture and gunstocks.
Wildlife & Ecology
Provides high-protein nuts for squirrels, woodpeckers, and other small mammals. It is the sole larval host for the Luna Moth. Large canopy provides significant nesting habitat for forest birds.