Black Walnut

Juglans nigra

Physical Characteristics

Juglans nigra is a deciduous Tree growing to 30 m (98ft) by 20 m (65ft) at a fast rate. See above for USDA hardiness. It is hardy to UK zone 4 and is not frost tender. It is in flower from May to June, and the seeds ripen in October. The species is monoecious (individual flowers are either male or female, but both sexes can be found on the same plant) and is pollinated by Wind. The plant is self-fertile. It is noted for attracting wildlife. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils and prefers well-drained soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It cannot grow in the shade. It prefers moist soil.

Distribution

Eastern N. America - Massachusetts to Florida, west to Texas and Minnesota.

Habitats

Woodland Garden Canopy;

Edible Uses

Edible Parts: Oil Sap Seed Edible Uses: Oil Sweetener Seed - raw or cooked. A sweet, rich distinctive delicious flavour it makes an excellent dessert nut and is also widely used in confections, cakes etc[2, 34, 82, 183]. The kernel is hard to extract and the oil it contains quickly turns rancid[101, 159]. The unripe fruits can be pickled[183]. The seed is borne in solitary fruits or in pairs and is 3 - 4cm in diameter[82, 229]. The nuts can leave a permanent stain on clothing[226]. An edible oil is obtained from the seed[101, 183]. A sweet taste but it tends to go rancid quickly[159]. Used as a seasoning in bread, squash and other foods[183]. The tree yields a sweet sap that can be drunk or concentrated into syrup or sugar[101, 102, 183]. It is tapped in spring.

Medicinal Uses

Alterative Anodyne Antiinflammatory Astringent Blood purifier Detergent Eczema Laxative Leprosy Pectoral Vermifuge The bark and leaves are alterative, anodyne, astringent, blood tonic, detergent, emetic, laxative, pectoral and vermifuge[4, 222, 257]. Especially useful in the treatment of skin diseases, black walnut is of the highest value in curing scrofulous diseases, herpes, eczema etc[4]. An infusion of the bark is used to treat diarrhoea and also to stop the production of milk, though a strong infusion can be emetic[21, 257]. The bark is chewed to allay the pain of toothache and it is also used as a poultice to reduce the pain of headaches[222, 257]. The juice from the fruit husk is applied externally as a treatment for ringworm[222, 257]. The husk is chewed in the treatment of colic and applied as a poultice to inflammations[222]. The burnt kernels, taken in red wine, are said to prevent falling hair, making it fair[269]. Green husks are supposed to ease the pain of toothache[269]. A tea made from the leaves is astringent[222]. An infusion has been used to lower high blood pressure[257]. It can be used as a cleansing wash[21]. The pulverized leaves have been rubbed on the affected parts of the body to destroy ringworm[257]. The oil from the ripe seeds has been used externally in the treatment of gangrene, leprosy, and wounds[269]. The sap has been used to treat inflammations[257].

Known Hazards

The plant has occasionally been known to cause contact dermatitis in humans[274].