Black Walnut
Juglans nigra · Deciduous Broadleaf Hardwood
Plant Family
Juglandaceae
Tree Category
Nut Tree / Shade Tree / Timber Tree
Variety / Cultivar
Native species
Hardiness Zones
USDA Zones 4-9; highly adaptable to climate variations within the temperate regions of North America.
About This Tree
A large, stately tree with an open, spreading crown and an oval to rounded form. It typically features a long, straight trunk when grown in forests, but becomes more spreading in open areas. It is known for its fast growth rate when young and its distinctively aromatic foliage.
Leaf Characteristics
Pinnately compound, 12-24 inches long, consisting of 11-23 leaflets. Leaflets are ovate-lanceolate with finely serrated margins. Foliage is medium green, turning a clear yellow in the fall before dropping.
Bark Characteristics
Dark gray to blackish, deeply furrowed into thin, diamond-shaped ridges. The inner bark turns dark chocolate brown upon exposure. Texture becomes increasingly rugged and corky with age.
Growing Information
Origin Region
Central and Eastern United States and Southern Ontario, Canada; thrives in fertile, well-drained bottomlands.
Growing Season
Leafs out late in spring and is among the first to drop leaves in autumn. Flowering occurs in late spring (May-June), with nut ripening in September-October.
Sunlight & Water Needs
Requires full sun for optimal growth. Prefers deep, moist, rich, well-drained soils. Once established, it has moderate drought tolerance but performs best with consistent moisture.
Mature Size
Reaches 70-100 feet in height with a spread of 60-80 feet. Growth rate is moderate to fast; can live for 150-250 years. Trunk diameter often reaches 2-4 feet.
Special Characteristics
Produces highly valued dark, straight-grained timber. Known for 'allelopathy,' as the roots, husks, and leaves produce juglone, a chemical that inhibits the growth of certain other plants like tomatoes and azaleas.
Wildlife & Ecology
Provides critical high-protein food for squirrels and other rodents. Supports over 100 species of Lepidoptera (moths/butterflies). Large branches provide nesting sites for various raptors and cavity-nesting birds.