Black Walnut

Media
Illustration of black walnut compound leaf and nuts.
Safety Concerns
Name
Edible
Scientific Name
Juglans nigra
Family
Juglandaceae (walnuts)
Description

Black walnut is a large tree with a straight trunk and rounded, open crown. The nuts, spicy odor, large feather-compound leaves, and chambered pith in the twigs help identify it.

Leaves are alternate, compound, 1–2 feet long, with 11–23 leaflets. Leaflets 3–5 inches long, 1–2 inches wide, broadest below the middle, the end leaflet smaller than side ones or absent; margin toothed; upper surface yellow-green; lower surface paler, hairy.

Bark is grayish-brown or black, grooves deep, ridges broad with sharp or rounded edges, roughly forming diamond-shaped patterns, chocolate-colored when cut.

Twigs are stout, rigid, brown to gray-brown, hairy; end bud about ½ inch long; pith light brown, chambered when cut lengthwise.

Flowers April–May. Male flowers in catkins, female flowers in a short spike on the same tree.

Fruits September–October, usually single or in pairs. A green, rounded husk, 1½–2½ inches across, covers the round, hard, bony, dark brown or black nut. The kernel is oily, sweet, and edible.

Similar species: Butternut, or white walnut (Juglans cinerea), is scattered and declining in the eastern two-thirds of Missouri, mostly in low and moist soils. It has rather cylindrical fruits, and the nut inside has 4 lengthwise ribs; leaf scars have the upper edge straight (not notched), bordered by a well-defined velvety ridge. The mild-tasting English (or Persian) walnut is the species J. regia. It is native to Eurasia and when cultivated in Missouri does not escape. The state of California grows nearly all of the US commercial supply of English walnuts. Walnuts are in the same family as hickories and pecans.

Size

Height: to 90 feet.

Where To Find
image of Black Walnut Distribution Map

Statewide.

Black walnut grows throughout Missouri in a variety of soils. It grows best on the deep, well-drained soils of north Missouri and on alluvial (river-deposited) soils in the south. Every farm in the state should grow some walnut trees. In addition to providing valuable wood, the walnut’s nutmeats are a major industry in the state. Even the hard shells can be used as an abrasive and to make activated carbon. It is Missouri’s most valuable tree.

Black walnut has been designated as Missouri's official state tree nut. Most of the state’s large, old walnut trees were felled in previous decades for lumber and other uses, yet the superb wood from this species remains in high demand. Young landowners have been planting walnuts in hopes of harvesting them in future decades. Several serious pests may endanger the health of Missouri's walnuts; educate yourself about thousand cankers disease (TCD), ambrosia beetles, walnut anthracnose, and other diseases, and never, ever transport firewood.

Missouri is the world’s top producer of black walnuts, which are used in baking and confections and even pickled whole. It would probably be eaten by more people if getting the nutmeats out of the nut were easier.

Walnut is the finest wood in the world. In the past, the warm brown hardwood was used lavishly in homes, barns, and fences. Today it’s used for furniture, veneer, and gunstocks.

There are records of oldtime Ozarkers scattering the fresh leaves of black walnut, or of its close relative, butternut, about the house to repel insects such as bedbugs and fleas.

The nuts are eaten by mice and squirrels.

The leaves are eaten by larvae of luna moths, regal moths, and others. The presence of such caterpillars naturally attracts warblers and other insectivorous birds.

Walnut trees produce a chemical, juglone, that stunts or kills other plants growing nearby.

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Similar Species

Where to See Species

Hayes Spring Conservation Area was purchased in 2005. The area contains Hayes Spring Cave and Spring which discharges into Dry Crane Creek.
This is a mostly forested area that contains the old Rosati fire tower. The tower is no longer used for fire detection purposes.
Tywappity Community Lake is located in Scott County, near the towns of Cape Girardeau, Chaffee, Scott City, Benton, and Oran.
This area offers access to the Big Piney River with a boat ramp.
About Trees, Shrubs and Woody Vines in Missouri
There are no sharp dividing lines between trees, shrubs, and woody vines, or even between woody and nonwoody plants. “Wood” is a type of tissue made of cellulose and lignin that many plants develop as they mature — whether they are “woody” or not. Trees are woody plants over 13 feet tall with a single trunk. Shrubs are less than 13 feet tall, with multiple stems. Vines require support or else sprawl over the ground.