Black Walnut: Key Facts

Did you know that black walnut trees have a wide variety of uses? Or that they may even be able to kill parasites? Keep reading to learn more about these and other black walnut key facts!

Quick Facts About Black Walnuts

Scientific Name:Juglans nigra
Type of Organism:Deciduous tree
Physical Description:Tall deciduous tree with large, fern-like leaves and hard, tennis-ball-shaped fruit. The green-yellow leaves are composed of 15 to 25 oppositely-arranged leaflets; each leaflet is serrated and may be up to 5 inches long. The fruits are lime green and composed of three layers: the outer husk, the inner hard shell, and the nutmeat. Black walnuts have tall trunks covered in gray-brown bark which is deeply ridged in a diamond-shaped pattern.
Distribution:Native to midwestern and eastern portions of North America, but may be cultivated in many temperate climates.
Habitat:Found primarily in mixed deciduous forests and woodlands, growing near rivers or streams, hilly areas, and savannas.
Size:50 to 150 feet tall; averaging 70 to 80 feet tall.
Average Lifespan:At least 200 years
Edible:Yes: black walnut nutmeats are edible.
Medicinal:Yes: nutmeats, leaves, bark, and husks may be used to make teas and tinctures to treat a variety of ailments.
Other Uses:– The wood is prized as lumber.
– The husks can be used to make dye.
– The trees are often planted as ornamentals.

What are Black Walnut Trees?

Black walnut trees grow in deciduous forests and temperate regions throughout the eastern half of North America. They produce hundreds of fruits each year which squirrels and other wildlife eat to survive throughout the winter.

Their bright green leaves, composed of many individual leaflets, give the trees a distinctive look. The fruits fall to the ground from late summer through late fall, with their lime-green husks turning a tarry black as they age.

Black walnut trees have many uses: their wood makes an excellent lumber; their nuts are full of flavor; and various parts of the tree have impressive health benefits. Pigments in the husks can be extracted and used to make a dye.

To learn more about these trees, check out the following video:

What are Some Interesting Facts About Black Walnut Trees?

  • Killer trees: Black walnuts produce a chemical called juglone, which can stunt or kill many different kinds of plants. As a result, plants such as potatoes, hydrangeas, and blackberries cannot grow near walnut trees.
  • Skin irritants: You may already know that black walnuts can stain your hands, but they can also cause blistering and skin irritation as well. This is again due to the chemical juglone, which is highly concentrated in black walnut husks.
  • Anti-parasitic: Black walnut husks are thought to be able to kill and expel parasites from the body. Though there is only anecdotal evidence for this, many people claim that taking an extract or tincture made from the husk for several days will rid you of parasites.


Black walnut trees are hardy deciduous trees found throughout much of the eastern U.S. They contain chemicals that can stain and blister your hands and kill a variety of sensitive plants; at the same time, they produce flavorful nuts, prized wood, and make excellent landscaping trees.

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