History of walnut

Walnuts belong to the genus Juglans, of the walnut family Juglandacae. Ancestral forms of walnut once spanned Europe, Asia and the Americas as far as north as Alaska.

Climate changes altered the geographic distribution and further evolutionary pressures resulted in the 21 species of Juglans in existence today.

All species produce nuts but the Persian or English walnut (Juglans regia) is the only species widely cultivated for nut production. The name Persian walnut is descriptive of its origin. Since Roman times, the English walnut had been cultivated commercially in Europe.

The walnut tree was introduced into Europe by the Romans and has been grown there since the 4th century. The Greeks cultivate the tree intensively, mainly for walnut oil, and the Romans regarded it as a sacred tree.

The word walnut may be derived from ‘wealh nut’, ‘wealh’ meaning foreign in Anglo-Saxon or old German. Trees of the species were in England by 1562 and nuts were brought to America by the earliest settlers.

The American colonist are said to have called the species ‘English’ walnut because it was brought to America on English ship and to distinguish it from the native American eastern black walnut (J. nigra). Black walnuts are native to the Central Mississippi Valley and the Appalachian region of North America. Black walnuts were an important source of food for the American Indians and early settlers.
History of walnut