Black Walnut: Juglans nigra

Plant Family & Name:

a. Juglandaceae (Walnut family)

b. Juglans comes from the Latin Jovis glans, meaning “nut of Jupiter,” referring to the walnut as a prized or noble nut. Nigra means “black,” referring to the dark-colored bark, heartwood, and especially the dark husk surrounding the nut.

Black walnut is also commonly called American black walnut, eastern black walnut, and Virginia walnut.

The tree is easily recognized by its large compound leaves, deeply furrowed dark bark, round green fruits, and the distinctive dark staining produced by the outer husk.

Habitat & Ecological role: Black walnut is a large, long-lived deciduous tree native to eastern and central North America. It commonly grows in rich bottomlands, floodplains, river valleys, fertile woodlands, woodland edges, and disturbed areas.

It prefers deep, fertile soils and adequate moisture and can become one of the dominant trees in rich forest ecosystems. Its nuts are an important food source for squirrels, birds, and other wildlife. The dense wood is also highly valued for furniture, cabinetry, flooring, and woodworking.

The green husks eventually fall from the tree and decompose, returning organic matter and chemical compounds to the soil.

*Black walnut produces a chemical compound called juglone, particularly concentrated in the roots, bark, leaves, and green fruit husks. Juglone can inhibit the growth of some neighboring plants, giving black walnut a competitive advantage and influencing the plant community around the tree.

Parts Used: Green hulls, bark, leaves, and nuts.

Herbal Actions: Astringent, antimicrobial, antifungal, antiparasitic, alterative, drying, vulnerary, bitter, cleansing.

Season: Late summer to early autumn for green hulls

Spring for young leaves and bark

Taste: Bitter, astringent, earthy, pungent, drying.

Energetic Qualities: Warm, dry, stimulating, astringent, penetrating, cleansing, contracting.

Indications: used for skin conditions, fungal infections, excessive moisture, intestinal complaints, and situations associated with microbial or parasitic imbalance.

Black walnut has a particularly strong traditional reputation as an external antimicrobial and antifungal herb.

Body system affinities: Integumentary, digestive, intestinal, lymphatic, immune.

Safety: *Black walnut is a strong, concentrated medicinal herb and should be approached differently from gentle nutritive herbs such as violet or cleavers. The green hull and other medicinal parts contain significant amounts of tannins and other biologically active compounds. Concentrated internal preparations may cause gastrointestinal irritation or other adverse effects. Black walnut can also cause skin irritation or allergic reactions, especially when used repeatedly or in concentrated topical preparations. The fresh green hull can stain and irritate the skin. Avoid applying concentrated black walnut preparations to broken or damaged skin unless specifically directed by a qualified practitioner. People with nut allergies should use particular caution, especially with preparations that may contain walnut proteins or other nut-derived components.Medicinal use during pregnancy and breastfeeding is best approached conservatively because adequate safety information is lacking.Because black walnut is sometimes promoted as a parasite cleanse, it is important not to rely on it as a substitute for diagnosis and appropriate treatment of a confirmed intestinal infection.

Experience: Black walnut has a very different personality from the gentle spring herbs. Its signature is immediately apparent when you work with the green hull.