Black Walnut
Juglans nigra · Deciduous broadleaf hardwood
Plant Family
Juglandaceae
Tree Category
Shade Tree, Nut Tree, Forest Tree
Variety / Cultivar
Species type (wild type, no specific named cultivar identified)
Hardiness Zones
Thrives in USDA Hardiness Zones 4 through 9.
About This Tree
A large, stately deciduous tree with a straight trunk, an open, rounded to oval crown, and coarse branching. Known for producing valuable hardwood timber and edible nuts, as well as releasing juglone, a chemical that inhibits the growth of certain other plants.
Leaf Characteristics
Pinnately compound leaves, typically 12 to 24 inches long, featuring 15 to 23 leaflets. Leaflets are ovate-lanceolate, finely serrated along the margins, pointed at the tip, and alternate in arrangement along the stem. They are yellowish-green above and paler, softly pubescent below.
Bark Characteristics
Dark brown to nearly black, deeply furrowed with thick, rounded ridges forming a distinctive diamond-shaped pattern that becomes more pronounced with age.
Growing Information
Origin Region
Native to eastern and central North America, well-adapted to rich alluvial soils along streams and in mixed forests.
Growing Season
Leafs out late in spring, drops leaves relatively early in autumn. Flowers appear in spring (April to May) concurrently with new leaves. Nuts mature and drop in autumn (September to October). Best planted in early spring or autumn.
Sunlight & Water Needs
Requires full sun for optimal growth and nut production. Prefers deep, rich, moist, and well-draining soils. Moderate drought tolerance once established, but performs poorly in dry, shallow, or waterlogged soils.
Mature Size
Mature height of 50 to 75 feet (sometimes up to 100 feet) with a comparable spread of 50 to 75 feet. Growth rate is moderate to fast. Long-lived, often exceeding 130 years.
Special Characteristics
Highly valued for its rich, dark brown durable timber used in fine furniture and cabinetry. Produces edible nuts enclosed in a solid green husk. Exhibits allelopathy through the production of juglone, which inhibits the growth of plants like tomatoes, apples, and birches.
Wildlife & Ecology
Supports various wildlife species, including squirrels and other rodents that feed on and cache the nuts. Provides nesting sites and cover for numerous bird species. Leaves are consumed by the caterpillars of several moth species.