Black Walnut
Juglans nigra · Deciduous, Broadleaf, Hardwood
Plant Family
Juglandaceae
Tree Category
Shade Tree, Nut Tree, Forest Tree
Variety / Cultivar
None specified; identification based on wild species characteristics.
Hardiness Zones
USDA Zones 4-9; highly adaptable to various temperature extremes across North America.
About This Tree
A large, stately tree with a typically open, rounded crown. Known for its high timber value and edible nuts. It grows straight in forest settings and is a long-lived canopy tree reaching up to 250 years.
Leaf Characteristics
Pinnately compound leaves, 1-2 feet long with 15-23 leaflets. Leaflets are ovate-lanceolate with finely serrated margins. Foliage turns a clear yellow in the autumn.
Bark Characteristics
Thick, dark grey-brown to blackish; deeply furrowed into narrow, diamond-shaped ridges. The inner bark turns chocolate brown when cut.
Growing Information
Origin Region
Eastern North America (Native from Canada to Florida and west to the Great Plains)
Growing Season
Late spring leafing; summer fruiting; deep dormant period starting in mid-to-late autumn. Often the last to leaf out and first to drop leaves.
Sunlight & Water Needs
Full Sun required; prefers moist, well-drained, fertile loams; moderate drought tolerance once established but prefers consistent moisture.
Mature Size
75-100 feet tall with a spread of 50-75 feet; moderate to fast growth rate; trunk diameter of 2-4 feet at maturity.
Special Characteristics
Produces juglone (an allelopathic chemical that inhibits many other plants); highly prized 'black' heartwood used for fine furniture; nuts are edible but have extremely hard shells.
Wildlife & Ecology
Provides critical food for squirrels and other rodents; attracts various moths including the Luna Moth; provides nesting sites for large birds. The juglone in soil creates a unique ecological niche for tolerant plants.