Facts About English Walnut Trees

English walnut trees (Juglans regia) are native to the Carpathian Mountain region in eastern Europe, but they grow in temperate climates around the world. English walnut trees are commercially cultivated for their fine-grained wood and edible nuts.

English walnut trees grow between 40 and 60 feet tall with an equal spread. They have smooth, gray bark, a spreading, rounded crown and pinnately compound leaves, which means that 5 to 7 pairs of leaflets grow opposite one another on a leaf stem. The male trees produce catkins, or flower clusters that have no petals, while females produce short, spiky flowers that are replaced by edible nuts.

English walnut trees grow in United States Department of Agriculture plant hardiness zones 3 through 7, which includes cities such as Tomahawk, Wis., Columbia, Mo., and Oklahoma City, Okla. They prefer well-drained, nutrient-rich soil and full sunlight. English walnut trees are susceptible to attack from caterpillars and webworms. They are also susceptible to anthracnose, leaf spot and root rot, among other diseases.

English walnut roots produce toxic chemicals called juglones that damage or kill many plant species such as tomatoes, potatoes, peonies and azaleas, among others. The nuts, which mature in the fall, can be messy. The trees have a deep taproot that makes transplanting difficult. Plants For A Future recommends only pruning trees when they are dormant; they bleed profuse amounts of resin and become weak from pruning injuries.