This species is a large (to 33 m), fast growing native of North America. It has a good, strong timber, but is less attractive than J regia. Nevertheless, extremely high prices are paid for the timber. In the USA one log fetched $30,000 in 1986.
The nuts are unique among commercial nuts in retaining their flavour when cooked. Nutri-tional composition of the black walnut per 100 grams of edible portion is: Water - 3.1 %, Energy - 628 calories, Carbohydrate - 14.8 g, Fat - 59.3 g, Protein - 20.5 g, Ash - 2.3 g, Calcium - trace, Potassium - 460 mg, Sodium - 3 mg, Magnesium - 190 mg, Iron - 6.0 mg, Phosphorous - 570 mg, Vitamin A - 300 I.U., Thiamin - 0.22 mg, Riboflavin - 0.11 mg, Niacin - 0.7 mg and the digestion time is 3 hours.
The bark is used as an astringent, the leaves as a detergent, the rind as an hepatic. The bark infusion or decoction is taken for diarrhoea, to stop milk production and as a mouthwash. For ringworm the green rind of the nut is used as a poultice.
This tree is used as a root -stock for J. regia (budding is used in preference to grafting).
- Juglans nigra (Eastern black walnut): Generally takes 10-12 years to start producing nuts.