English walnut trees supply the world with commercial walnuts. There are physical characteristics, habitat and common diseases that afflict the tree.
The English walnut tree originates from the Persian walnut, which was cultivated by the Greeks and disbursed around Europe by the Romans. Franciscan monks brought the English walnut to California in the 19th century.
English walnut trees have a compound leaf, meaning a stem connects several small leaves together, forming one large leaf. English walnuts have a single leaf at the top and three leaves in decreasing size on either side of the stem.
English walnut trees reach a maximum height of 60 feet after 20 years of growth. It blooms in mid-spring, grows throughout spring and summer, and looses its leaves in the fall without turning colours.
English walnut trees require climates with at least 190 days free from frost, 28 to 45 inches of rain a year and plenty of access to sunshine.
Diseases and Pests
English walnut trees deal with diseases and pests, including squirrels, the larva of the walnut husk fly and the codling moth, aphids, leaf-chewing caterpillars, crown rot, walnut blight, blackline (virus), and scale.