Black Walnut
Juglans nigra · Deciduous Broadleaf Hardwood
Plant Family
Juglandaceae
Tree Category
Shade Tree / Nut Tree / Forest Tree
Variety / Cultivar
Wild / Straight species (e.g., cultivars include 'Thomas' or 'Emma K' grown for nut production)
Hardiness Zones
USDA Hardiness Zones 4 through 9
About This Tree
A large forest and shade tree reaching up to 100 feet tall with an upright, open, rounded canopy. Known for its dark, deeply furrowed bark with a distinctive dark chocolate-brown interior when cut, large pinnately compound leaves, and round green hulls enclosing edible walnuts.
Leaf Characteristics
Pinnately compound, 12 to 24 inches long with 15–23 narrow lanceolate leaflets. Leaflets are light to medium green with finely serrated margins, turning yellow in fall before dropping early.
Bark Characteristics
Deeply furrowed with prominent dark gray-brown to blackish blocky ridges forming a diamond pattern. When scraped or cut, the inner bark reveals a rich, dark chocolate-brown color.
Growing Information
Origin Region
Native to central and eastern North America, from southern Ontario through the eastern United States west to the Great Plains.
Growing Season
Leafs out in late spring (May), flowers in May to June, fruits ripen in late summer to autumn (September–October), drops leaves early in autumn.
Sunlight & Water Needs
Requires full sun for optimal growth. Prefers moist, well-drained, deep fertile soils; moderate drought tolerance once mature.
Mature Size
70 to 100+ feet tall, 50 to 70 feet spread; growth rate is moderate to fast when young; lifespan up to 150-250 years; trunk diameter 2 to 4+ feet.
Special Characteristics
Produces juglone, an allelopathic compound that inhibits growth of certain surrounding plant species. Highly valued timber wood used for fine furniture and woodworking. Produces rich, flavorful edible nuts.
Wildlife & Ecology
Nuts provide a vital food source for squirrels, mice, and other rodents. Hosts numerous caterpillar species including the Luna moth and Walnut Caterpillar. Provides nesting cover for birds.