Other Walnut Species

Of the American species of walnut, cultivated on a smaller scale, the most important is the American black walnut, J. nigra, often regarded as the national tree of the USA, although its native range is confined to the eastern half of the country. The nut has a thick, hard shell, blackish-brown in colour, difficult to crack without breaking up the kernel. The flavour is stronger than that of a Persian walnut, but pleasant; and stands up better to cooking than that of the Persian walnut.

The butternut or American white walnut, J. cinerea, also grows in the eastern states, and also has a troublesome hard shell. As its name suggests, it is light in colour and the juice does not stain. The kernel has a strong but good flavour, which some prefer to that of the Persian walnut, and is more oily. Indeed, when white settlers arrived they adopted the practice of American Indians and used it as a source of oil. The California walnut, J. californica, is native to that state.