English Walnut

Sowing: English Walnut is typically direct-sown and grows best in full sun with deep, rich, loamy, well-drained soil; it does not tolerate shade, poor soils, or waterlogged ground, and it struggles in hot, humid climates. Because it develops a deep taproot, it is also difficult to transplant once established, so it is often propagated instead by grafting, layering, seed, or stem cuttings.

Growth: A young tree begins producing nuts at four to six years old, but a good crop is not expected until the tree reaches fifteen to twenty years of age.

Pests: English Walnut has no serious insect or disease problems, though webworms and caterpillars occasionally chew its foliage. Anthracnose, bacterial blight, root rot, canker, leaf spot, and shoot dieback can also occur.

Toxicity: The tree's roots release a compound called juglone, which is toxic to nearby plants such as azaleas, rhododendrons, blueberries, peonies, tomatoes, peppers, and potatoes, a factor worth weighing when siting the tree near other plantings.

The nuts mature in fall, their smooth green husks turning brown as they ripen around a thin, wrinkled shell. Fallen nuts and husks can create considerable litter beneath the tree once they drop.

Culinary: English Walnut is grown commercially for its edible kernel, a nutrient-dense, oil-rich seed that can be pressed for walnut oil; the oil is dominated by unsaturated fatty acids, mainly linoleic acid with lesser amounts of oleic and linolenic acids, and can be consumed without refining.

Timber: Its wood is used to make furniture, cabinets, and gunstocks.

Ornamental: The tree is also planted as a large ornamental and shade tree in landscapes, and it serves as a larval host plant for the hickory horndevil moth.

Traditional: Historically, English Walnut was used as a folk remedy for a range of ailments, including anthrax, asthma, backache, colic, and rheumatism.

English Walnut's native range extends from southern Europe and the Caucasus through Central Asia to the Himalayas and China, with wild populations recorded in countries such as Afghanistan, Iran, Iraq, Turkey, and Pakistan. From this native range it was carried into cultivation across much of Europe and beyond, and it was later introduced to the West Coast of the United States, where about 99 percent of the country's commercial walnut crop is now grown in California.