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Juglans nigra (black walnut)

A North American tree with dark-coloured timber and bark, black walnut produces timber and edible nuts (seeds) used in confectionery.
Juglans nigra at Kew Gardens

Juglans nigra at Kew Gardens

Species information

Scientific name: 

Juglans nigra L.

Common name: 

black walnut, American walnut

Conservation status: 

Not assessed according to IUCN Red List criteria.


Mixed woodland.

Key Uses: 

Timber, edible seeds, ornamental.

Known hazards: 

See below.


Genus: Juglans

About this species

Black walnut gets its name from both its dark timber and dark brown to black bark. All walnut trees (Juglans species) produce edible seeds (known commonly as nuts), but those of black walnut are notoriously difficult to extract from their husks; it is the common walnut, Juglans regia, that is cultivated commercially for its nuts.

The leaves, bark and fruits of black walnut contain juglone, a red crystalline compound, which is known to be active against tobacco mosaic virus (a virus that causes an infectious disease in crops such as tobacco and tomatoes). When rubbed, the leaves of black walnut give off a strong aroma that most people find pleasant.

Medicinal Uses

Black walnut was used medicinally by Native Americans to treat skin conditions, psychological illness and miscellaneous diseases.


Wallia nigra (L.) Alef.


main info

Courses at Kew

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Kew offers a variety of specialist training courses in horticulture, conservation and plant science.

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