Black walnut, Juglans nigra, is so close a relative to the European or English walnut, Juglans regia, that the herbalists often talk about, and use, them synonymously.

Juglans nigra is native to North America and was used by Native Americans for food, wood and medicine. The green hull was sought after for its reputed medicinal virtues, but there is a warning in Grieve's description: 'The husk, shell and peel are sudorific, especially if used when the Walnuts are green. Whilst unripe, the nut has wormdestroying virtues.'

The German Commission E has concluded that 'Since the effectiveness for the claimed uses is not documented and risks are known, the application of walnut hull preparations cannot be justified.'

Use of Walnut hulls is best confined to their insect-repelling and dying functions.

Grieve's classic 'A Modern Herbal': 'No insects will touch the leaves of the Walnut, which yield a brown dye, which gypsies use to stain their skin. It is said to contain iodine.'

'The husks and leaves, macerated in warm water impart to it an intense bitterness, which will destroy all worms (if the liquid be poured on to lawns and grass walks) without injuring the grass itself.'

'The green husks of the fruit, boiled, make a good yellow dye.'

Walnut Hull Basket Dye:

Walnut hulls makes a brown basket dye. Boil the crushed hulls in a stocking or other mesh holder, then let cool and soak overnight. Immerse your basket in the dye liquor – the longer the immersion, the darker the stain. The stain can also be painted or sprayed. The hulls are reusable and will make more than one batch of dye.