Location of Black Walnut

Common name: Black walnut

Family: Juglandaceae

Range: Europe, Eastern N. America - Massachussets to Florida, west to Texas and Minnesota.

Habitat: Rich fertile woods and hillsides in deep well-drained soils.

Walnuts belong to a family that includes the pecan and hickory pecan. There are three main varieties of walnut trees, the most familiar variety being Juglans regia, known as the Persian or English walnut. For the past two centuries its main growing region has been North America, specifically California. Southeastern Europe also grows many varieties of the English walnut which is also cultivated from Turkey to the Himalayas and even reaching into China. This variety grows to a height of 40 to 60 feet high and has a lifespan of about 60 years or more.

Juglans nigra, or the Black Walnut, grows mainly in the Eastern and Central United States, from New England to Minnesota and Nebraska, and south to the Gulf of Mexico. The black walnut can grow to a height of 150 feet, with the nuts bearing a more rounded shape. Though the tree is grown mainly for lumber, there is a minor industry in harvesting the nuts because of their distinctive, rich, and oily flavor that is valued for baking, candy-making, and preparing black walnut ice cream. The black walnut tree is known to be a centenarian, living for 100 years or longer.

All walnut trees are deciduous and grow well in temperate zones if sheltered from extreme cold and strong wind. They thrive best in deep, fertile soil free of alkali and should not be planted closer than 60 to 70 feet apart. The trees will grow easily on mountainsides up to an altitude of 3,000 ft.

Walnut groves must be irrigated frequently because the trees require an abundance of water to produce nut kernels that are moist and well developed. However, it is also necessary to provide good drainage. Deep watering in the winter is important.

In Europe the trees grow to a height of 60 to 85 feet with a typical trunk circumference of 3 feet. One farmer recorded a circumference of 16 feet in a farmers' almanac. In the United States walnut trees can grow to a height of 20 feet in 6 to 8 years and finally reach about 90 to 100 feet when mature.

Each tree produces both male and female flowers that bloom in April and May, about the same time the leaves begin to appear. Though the trees self-pollinate, most growers will plant one or two other varieties in the grove for optimum cross-pollination.

In the United States, California's Sacramento Valley is the center of walnut production, whereas in France, Perigord is known for its abundance of walnut groves that were thriving well before 1657.

Throughout Europe the two varieties of walnut are the Juglans regia, the familiar commercial walnut, and the black walnut, Juglans nigra. The English walnuts reach maturity in the early fall when the husks split open. The black walnut and the butternut also mature in the fall season.

The plant prefers light (sandy), medium (loamy) and heavy (clay) soils and requires well-drained soil. The plant prefers acid, neutral and basic (alkaline) soils. It cannot grow in the shade. It requires moist soil.