Walnut trees are majestic deciduous trees renowned for their delicious nuts, valuable timber, and ornamental beauty. Walnut species spread across North America, Europe, Asia, and South America, these trees offer diverse characteristics, from the rich, earthy nuts of the Black Walnut to the thin-shelled English Walnut prized in culinary applications.
Walnut trees are classified under the genus Juglans, derived from Latin “Jovis glans” (Jupiter’s acorn), reflecting their historical reverence. Part of the Juglandaceae family, alongside hickories and pecans, these trees are deciduous, typically growing 33–131 feet (10–40 meters) tall with pinnate, feather-like leaves containing 5–25 leaflets. They are monoecious, bearing both male (catkins) and f
emale (spiky clusters) flowers on the same tree, producing drupes—technically not true nuts but stone fruits with edible kernels encased in hard shells. The species vary in bark texture, leaf size, nut flavor, and growth habits, with key species like Juglans regia (English Walnut) and Juglans nigra (Black Walnut) dominating commercial and ornamental use. Their allelopathic compound, juglone, secreted by roots and leaves, inhibits nearby plant growth, making careful site planning essential.
Walnut trees have a rich history spanning thousands of years. The English Walnut (Juglans regia), native to Persia, was a staple in ancient Mediterranean diets, traded by English merchants, earning its common name. Black Walnuts (Juglans nigra), native to North America, were used by Indigenous tribes for food, dye, and medicine. During the Byzantine era, walnuts were called “royal nuts,” and their cultivation was documented in 12th-century Spain by Ibn al-‘Awwam.
In Greek mythology, walnuts symbolized fertility and wisdom, while in Kyrgyzstan’s Tien Shan, Juglans regia forests still provide food and fuel. Walnut wood has been prized for centuries, used in furniture, gunstocks, and even Confederate uniforms dyed with husk pigments. Today, China, the U.S., Iran, and Turkey lead global walnut production, with California’s Central Valley growing 99% of U.S. English Walnuts.
Walnut Trees
1. Black Walnut (Juglans nigra)
The black walnut, also known as the eastern black walnut or American walnut, is a native of North America, widely distributed across the eastern United States. This deciduous tree grows 70-100 feet tall with a broad, rounded canopy. Its dark, furrowed bark and pinnate leaves are distinctive, but it’s best known for its flavorful, nutrient-rich nuts and high-quality hardwood, used in furniture and cabinetry. Black walnut trees produce juglone, a chemical that can inhibit the growth of nearby plants, making companion planting challenging. They prefer deep, well-drained soils and full sun, thriving in USDA zones 4-9.
2. English Walnut (Juglans regia)
The English walnut, also called the Persian walnut, is the most commercially cultivated walnut species, valued for its thin-shelled, edible nuts. Originating in Persia, this tree is now grown worldwide, particularly in California, China, and Europe. It reaches 40-60 feet in height with a wide, spreading canopy and smooth, grayish bark. English walnuts are prized for their mild flavor and are used in baking, snacking, and oil production. These trees require well-drained, loamy soil and full sun, performing best in USDA zones 7-9. Grafted varieties like ‘Chandler’ ensure consistent nut quality.
3. Butternut (Juglans cinerea)
The butternut, or white walnut, is a North American species found in the northeastern U.S. and Canada. Growing 40-60 feet tall, it has light gray bark and compound leaves with a slightly fuzzy texture. Its oval nuts are sweet and oily but harder to crack than English walnuts. Butternut wood is lighter than black walnut and used for furniture and carving. Unfortunately, butternut canker, a fungal disease, has decimated populations, making conservation efforts critical. This tree prefers moist, fertile soils and partial shade, suitable for USDA zones 3-7.
4. California Black Walnut (Juglans californica)
Native to Southern California, the California black walnut is a smaller species, typically reaching 15-30 feet. It has dark, furrowed bark and a rounded canopy, often growing in chaparral and coastal regions. Its small, hard nuts are edible but less commonly harvested than other species. The tree’s wood is used for decorative items, and its dense foliage provides shade in xeriscaped gardens. California black walnuts are drought-tolerant and thrive in USDA zones 7-10, preferring well-drained soils and full sun.
5. Arizona Walnut (Juglans major)
The Arizona walnut, or Nogal, grows in the southwestern U.S. and northern Mexico, often along streambanks and canyons. This medium-sized tree, reaching 30-50 feet, has smooth, gray bark and feathery, compound leaves. Its small, thick-shelled nuts are edible and were historically used by Native American tribes. Arizona walnuts are well-suited to arid climates, requiring minimal water once established. They grow best in USDA zones 7-10 and prefer sandy or rocky soils with good drainage.
6. Andean Walnut (Juglans neotropica)
The Andean walnut, native to South America, is a slow-growing, tall tree reaching up to 100 feet. Its grooved, red-brown bark and oval canopy make it visually striking, while its edible nuts are a local delicacy. This species is less common in cultivation but valued for its timber and shade in tropical regions. Andean walnuts thrive in USDA zones 10-11, requiring warm, humid conditions and fertile, well-drained soils. They’re sensitive to frost, limiting their range in temperate climates.
7. Japanese Walnut (Juglans ailantifolia)
The Japanese walnut, native to Japan and Sakhalin, is a medium-sized tree growing 30-50 feet tall. Its broad, spreading canopy and heart-shaped nuts distinguish it from other species. The nuts are edible but smaller and thicker-shelled than English walnuts. Japanese walnuts are cold-hardy, thriving in USDA zones 4-8, and prefer moist, loamy soils. They’re often planted for ornamental purposes due to their attractive foliage and tolerance of urban conditions.
8. Manchurian Walnut (Juglans mandshurica)
Native to East Asia, the Manchurian walnut is a cold-hardy species growing 40-60 feet tall. Its dark green, pinnate leaves and small, round nuts are notable, though the nuts are less palatable than those of English walnuts. This tree is valued for its timber and as a rootstock for grafting other walnut species. It thrives in USDA zones 2-7, tolerating harsh winters and a range of soil types, provided they’re well-drained.
9. Little Walnut (Juglans microcarpa)
The little walnut, also known as the Texas walnut, is a shrubby tree native to the southwestern U.S. and northern Mexico. Growing 10-30 feet tall, it has small, thin-shelled nuts that are edible but rarely harvested commercially. Its compact size and drought tolerance make it ideal for xeriscaping and erosion control. Little walnuts prefer alkaline soils and full sun, thriving in USDA zones 6-9.
10. Hinds Black Walnut (Juglans hindsii)
The Hinds black walnut, native to Northern California, grows 30-60 feet tall with a narrow, upright canopy. Its nuts are small and hard, less desirable for eating but used by wildlife. This species is often used as a rootstock for English walnut orchards due to its resistance to soil-borne diseases. Hinds black walnuts prefer moist, fertile soils and full sun, thriving in USDA zones 7-9.
11. Heartnut (Juglans ailantifolia var. cordiformis)
A variety of the Japanese walnut, the heartnut is named for its distinctive heart-shaped nuts, which are sweet and easy to crack. Growing 30-50 feet tall, it has lush, tropical-looking foliage and a spreading canopy. Heartnuts are popular in permaculture and home orchards for their reliable nut production. They’re cold-hardy, thriving in USDA zones 4-8, and prefer well-drained, loamy soils.
12. Northern California Walnut (Juglans hindsii hybrid)
This hybrid, sometimes confused with Juglans hindsii, is a cross between Hinds black walnut and English walnut, commonly used as a rootstock in California orchards. Growing 40-60 feet tall, it has a sturdy trunk and dense foliage. Its nuts are not typically harvested, but the tree’s vigor and disease resistance make it valuable for commercial growers. It thrives in USDA zones 7-9, preferring deep, well-drained soils.
13. Carpathian Walnut (Juglans regia var. carpathian)
A cold-hardy cultivar of the English walnut, the Carpathian walnut is adapted to colder climates, thriving in USDA zones 5-9. Growing 40-60 feet tall, it produces large, thin-shelled nuts with a rich flavor. Its smooth, gray bark and wide canopy make it a popular shade tree. Carpathian walnuts require full sun and fertile, well-drained soils, making them ideal for northern orchards.
14. Chandler Walnut (Juglans regia ‘Chandler’)
The Chandler walnut, a cultivated variety of the English walnut, is one of the most popular orchard trees in the U.S., particularly in California. Growing 40-50 feet tall, it produces large, high-quality nuts with thin shells, ideal for commercial markets. Its upright growth and high yield make it a favorite among growers. Chandler walnuts thrive in USDA zones 7-9, requiring well-drained soils and full sun.
15. Franquette Walnut (Juglans regia ‘Franquette’)
The Franquette walnut, a popular cultivar of the English walnut, is widely grown in regions like California, Oregon, and France. This medium-sized tree, reaching 40-60 feet tall, is valued for its late blooming, which helps it avoid spring frosts, making it ideal for cooler climates. The Franquette produces medium to large nuts with a rich, buttery flavor and thin shells, perfect for both fresh consumption and processing. Its upright growth and attractive, light gray bark also make it a favorite for ornamental planting. Franquette walnuts thrive in USDA zones 6-9, requiring well-drained, fertile soils and full sun. Regular pruning and pest management ensure high yields, especially in commercial orchards.
16. Chinese Walnut (Juglans cathayensis)
The Chinese walnut, native to East Asia, particularly China, is a lesser-known species that grows 50-80 feet tall with a broad, rounded canopy. Its pinnate leaves are similar to other walnuts, but its small, round nuts have thick shells and a slightly bitter flavor, often used in traditional Chinese medicine and cuisine. The tree’s durable wood is used for furniture and tool handles, while its deep root system aids in erosion control. Chinese walnuts are cold-hardy, thriving in USDA zones 5-8, and prefer moist, loamy soils with good drainage. They’re less common in commercial cultivation but valued for their ecological benefits.
17. Siebold Walnut (Juglans sieboldiana)
The Siebold walnut, another Japanese native to Japan, is a medium-sized tree growing 30-50 feet tall, closely related to the Japanese walnut (Juglans ailantifolia). Its small, edible nuts have a mild flavor but are rarely harvested commercially due to their thick shells. The tree’s lush foliage and spreading canopy make it a popular ornamental in temperate regions. Siebold walnuts are highly adaptable, tolerating a range of soil types, including clay and sandy soils, as long as drainage is adequate. They thrive in USDA zones 4-8 and are resistant to many common walnut pests, making them low-maintenance for home gardeners.
18. Paradox Hybrid Walnut (Juglans x paradox)
The Paradox hybrid walnut is a cross between the California black walnut (Juglans californica) and the English walnut (Juglans regia), primarily used as a rootstock in commercial orchards. Growing 50-70 feet tall, this vigorous hybrid combines the disease resistance and drought tolerance of the California black walnut with the nut quality of the English walnut. While its nuts are edible, they’re not typically harvested, as the tree’s primary value lies in its strong root system, which supports grafted cultivars. Paradox walnuts thrive in USDA zones 7-10, preferring deep, well-drained soils and full sun.
19. Dryanovo Walnut (Juglans regia ‘Dryanovo’)
The Dryanovo walnut, a Bulgarian cultivar of the English walnut, is prized for its high yields and large, thin-shelled nuts with a sweet, creamy flavor. Growing 40-50 feet tall, this tree has a compact, upright form, making it suitable for smaller orchards and home gardens. Its early fruiting, often within 3-4 years of planting, appeals to growers seeking quick returns. Dryanovo walnuts are cold-hardy, thriving in USDA zones 5-9, and perform best in fertile, well-drained soils with consistent moisture. Regular fertilization and irrigation boost nut production, especially in drier climates.
20. Fernor Walnut (Juglans regia ‘Fernor’)
The Fernor walnut, another English walnut cultivar, is a French variety known for its adaptability to cooler climates and resistance to late frosts. Reaching 40-60 feet in height, it produces large, high-quality nuts with excellent flavor, ideal for fresh markets and confectionery. Its vigorous growth and disease resistance make it a favorite among European growers. Fernor walnuts thrive in USDA zones 6-9, requiring well-drained, loamy soils and full sun. Like other English walnut cultivars, it benefits from cross-pollination with varieties like Franquette for optimal yields.
21. Texas Black Walnut (Juglans nigra var. texana)
The Texas black walnut, a regional variant of the black walnut, is found primarily in Texas and Oklahoma. Growing 50-80 feet tall, it closely resembles the eastern black walnut but is better adapted to the hot, dry climates of the southern U.S. Its nuts are slightly smaller but equally flavorful, though the thick shells make extraction challenging. The tree’s dark, furrowed bark and dense canopy provide excellent shade, and its wood is used for furniture and flooring. Texas black walnuts thrive in USDA zones 6-9, preferring deep, moist soils but tolerating occasional drought.