Black Walnut
Juglans nigra · Deciduous, Broadleaf, Hardwood
Plant Family
Juglandaceae
Tree Category
Nut Tree, Shade Tree, Timber Tree
Variety / Cultivar
None (Wild type)
Hardiness Zones
USDA Zones 4-9
About This Tree
A large, stately forest tree with a high, rounded, open canopy. Known for its valuable dark heartwood and large edible nuts protected by thick green husks.
Leaf Characteristics
Pinnately compound leaves, 12-24 inches long, with 15-23 ovate-lanceolate leaflets. Fine-toothed margins, yellowish-green color, turning yellow in fall.
Bark Characteristics
Grey-brown to nearly black, deeply furrowed into diamond-shaped ridges. The inner bark turns dark chocolate brown when cut.
Growing Information
Origin Region
Eastern North America, commonly found from Ontario to Florida and west to Texas.
Growing Season
Late spring leafing (one of the last trees to leaf out), flowering in May-June, fruit ripening in autumn, early dormancy.
Sunlight & Water Needs
Full sun is essential (shade intolerant); prefers moist, well-drained, fertile loamy soils but has moderate drought tolerance once established.
Mature Size
70-100 feet tall with a similar spread. Growth rate is moderate. Lifespan typically 150-250 years.
Special Characteristics
Produces juglone (allelopathic) which inhibits growth of certain plants; highly prized for furniture-grade timber; deep taproot makes it difficult to transplant.
Wildlife & Ecology
Provides critical food for squirrels and rodents; host plant for the Luna Moth and Walnut Caterpillar; provides nesting sites for large birds.