The English Walnut and the Black Walnut are both trees grown in temperate climates, and cultivated for their fruit and their wood. Despite some differences, both English Walnut and Black Walnut trees produce a nutritious, delicious fruit enjoyed in many sweet and savory recipes.
English Walnuts and Black Walnuts are both plants of the genus Juglans. They are fruit-bearing trees that lose their leaves each year. English Walnuts, or Juglans regia, are also known as Persian Walnuts or Common Walnuts. Black Walnuts, or Juglans nigra, are also referred to as Eastern Black Walnuts.
The fruit of both trees is a nut with high nutritional value and pleasant taste. When walnuts are sold whole in their shells, they are most often English walnuts. English walnuts are ideal for being eaten from their shells, as the shell is relatively thin and easy to crack. Black walnuts, however, have a tough husk around their shell and a strong smelling, staining juice.
The meats often cannot be extracted whole as the shell grows into the meat. Black walnuts are therefore most often sold as pieces of nut meat. Black walnuts have a more robust flavor than English walnuts, which makes them popular for use in ice cream and baked goods.
The nutritional content of Black walnuts and English walnuts is very similar. Black walnuts have very slightly higher protein content and lower fat content. The walnuts can be used interchangeably in recipes, but the Black walnuts do have a more powerful flavor. All walnuts are a good source of alpha linolenic acid (ALA), an omega-3 fatty acid. ALA is recommended for the prevention of heart disease.
The English Walnut tree has a smooth bark with olive to grey color. The Black Walnut tree’s bark is deeply grooved, with a dark grey-black color. On both trees, each leaf is made up of many small leaflets. The Black Walnut has more leaflets (usually 15 to 23) and its leaflets are smaller and narrower than those of the English Walnut. English Walnut leaflets usually number between five and nine, and the leaflet shape is a wider oval.
Walnuts have been cultivated for millennia. The English Walnut originated in Persia. Walnuts were grown in the Hanging Gardens of Babylon (ca. 2000 B.C.) and there is mention of the walnut in the section of the Code of Hammurabi (ca. 1795 B.C.) governing the growing of food.
Greeks discovered the Persian Walnut and cultivated it to produce a larger fruit, more like the English Walnut we know today. The ancient Romans revered the walnut, and named it after Jupiter (also known as Jove) their most honored god. Whole, unshelled walnuts have been discovered in the ruins of Pompeii.
The Black Walnut is native to North America. Archaeological evidence shows that Native Americans were consuming walnuts as long ago as 2000 B.C. In addition to food use, Native Americans used the staining juice from the walnut’s husk as a dye.