Lady Bird Johnson Wildflower Center - The University of Texas at Austin information

 Native Plant Database

Juglans nigra


Black walnut, Eastern black walnut


Juglandaceae (Walnut Family)



Juglans nigra (Black walnut)
Wasowski, Sally and Andy
Black walnut is a large, rugged, deciduous tree, 50-75 ft. in height and width, sometimes reaching 150 ft. tall. Dark, furrowed bark on the trunk. Wide-spreading branches form an upright, umbrella-like crown in the woods or a round-topped crown in the open. The well-formed trunk is usually devoid of branches a considerable distance from the ground. Leaves up to 2 feet long with 5 to 11 pairs of leaflets along a central axis and a single leaflet at the tip; midrib of the lateral leaflets off-center with the wider part of the blade toward the leaf tip. Leaflets emerge very late in spring and are yellow-green. Fall color is clear yellow, unless the tree has been troubled with insects or leaf blight. Flowers inconspicuous, in elongate, green clusters. Fruit 1 1/2 to 2 1/4 inches in diameter, consisting of a hard-shelled, furrowed nut enclosed in a green husk, darker when ripe.

One of the scarcest and most coveted native hardwoods, Black Walnut is used especially for furniture, gunstocks, and veneer. Individual trees fetch attractive prices and a few prized trees have even been stolen. Since colonial days and before, Black Walnut has provided edible nuts and a blackish dye made from the husks. Tomatoes and apples do not survive near mature trees. The delicious nuts must be gathered early, before squirrels and other wildlife can consume them. Of all the native nut trees of North America, the Black Walnut is the most valuable save only the Pecan (Carya illinoinensis), and in the traditions of pioneer life and rustic childhood it is even more famous.

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Plant Characteristics

Duration: Perennial
Habit: Tree
Leaf Retention: Deciduous
Leaf Arrangement: Alternate
Leaf Complexity: Pinnate
Breeding System: Flowers Unisexual , Monoecious
Size Notes: 50-75
Leaf: Green
Autumn Foliage: yes
Fruit: Green, Brown
Size Class: 72-100 ft.

Bloom Information

Bloom Color: Yellow , Green , Brown
Bloom Time: Apr , May

Distribution

USA: AL , AR , CT , DE , FL , GA , IL , IN , IA , KS , KY , LA , ME , MD , MA , MI , MN , MS , MO , NE , NH , NJ , NY , NC , ND , OH , OK , PA , RI , SC , SD , TN , TX , UT , VA , WV , WI , WY , DC
Canada: ON
Native Distribution: W. MA to n.w. FL, w. to s. MN, n.e. NE, w. OK & c. TX
Native Habitat: Rich, moist woods; bottomlands

Growing Conditions

Water Use: High
Light Requirement: Sun , Part Shade
Soil Moisture: Moist
Soil pH: Circumneutral (pH 6.8-7.2)
CaCO3 Tolerance: High
Cold Tolerant: yes
Heat Tolerant: yes
Soil Description: Moist, rich soils. Sandy Loam, Medium Loam, Clay Loam, Acid-based, Calcareous
Conditions Comments: Black walnut is slow-growing especially if not in its preferred moist, fertile, sunny site. The deep tap-root makes transplanting difficult. Nuts may become a nuisance as they litter and stain. Foliage is often attacked by caterpillars, and the species is susceptible to anthracnose which defoliates trees for the season.

Benefit

Use Ornamental: Fall conspicuous, Shade tree
Use Wildlife: Squirrels are among the few creatures with strong enough teeth and the determination to gnaw through the extremely hard shells.
Use Other: Certain plants will not grow under Black Walnut trees because of the juglones that the tree puts in the soil. Walnut husks are rich in tannins and toxins. Ground husks have provided insecticides, fish poison and black dye.
Fragrant Foliage: yes
Attracts: Birds , Butterflies
Larval Host: Black walnut is the preferred host of the luna and regal moth.

Last Update: 2013-06-27