The spread canopy of walnut trees is green, lush foliage and they are big deciduous trees. The bark of most walnut trees is dark and ridged, with pinnate feathery leaves and globular drupes. Walnut trees have a broad spread of up to 50 feet (15 meters) and grow to heights of 33 to 131 feet (10 meters).
The delicious nuts and lovely wood of walnut trees make them famous members of the plant genus Juglans. This walnut tree identification guide will help you determine the various species in the genus. Varieties of walnut tree leaves, nuts, and bark are described in this section.
Walnut Tree Facts
The walnut family Juglandaceae contains 21 species of walnut trees. Black walnut and English walnut trees are the two most common walnut tree types. Butternut, California black walnut, Andean walnut, Japanese walnut, and little walnut are other varieties of the walnuts tree. Walnut trees are found in Europe, North America, Asia and China, among other places.
The delicious nuts that walnut trees produce are the most common association. The walnut fruit is really a drupe, not a nut, according to botanical terms. The seed of the walnut tree is what is referred to as the nut. The fruit of the walnut is a hard shell that encloses the seed (which we call walnut) and has an outer fleshy green husk. The look of a walnut is comparable to that of a brain.
Furniture is made of walnut wood, which is a premium hardwood. Walnut wood has a dark brown color that is almost chocolatey. It’s perfect for carving bowls, constructing cabinets, or using it as a veneer because of its beautiful grain and walnut wood color.
Walnut Tree Varieties
The genus Juglans contains 21 species in the Juglandaceae family of large deciduous trees.
- Black walnut (Juglans nigra). The dark-colored bark of the black walnut tree has deep furrows, giving the tree trunk a rough feel. The foliage of black walnuts is made up of pinnate leaves and the nuts are grown in a rounded green husk.
- Butternut (Juglans cinerea) Walnut trees, or white walnut trees, are used. The bark of butternut trees is lighter and has a more polished look than black walnuts. Butternut tree leaves are pinnate with up to 17 leaflets, like all walnut species. Drupes have an oval shape, not a rounded one.
- English walnut (Juglans regia) Trees are utilized to make a variety of items. The bark of juvenile English walnut trees is olive-brown, with shallow fissures that turn into a complete coat as they grow up. The pinnate leaves of walnut trees are smaller than those of other species of walnut. The walnut fruit is sweet and can be found all over the tree.
Walnut Tree Bark
The bark of walnut trees is generally rough and fissured. The trunk is ridged vertically from top to bottom. Walnut bark may be light gray to dark brown depending on the species. The inner color of English walnut or black walnut wood is dark brown, when the bark is removed.
The walnut species can be distinguished by their bark. The touch of butternut (white walnut) bark is silky and smooth. The black and English walnut bark have deep vertical grooves and are a darker hue.
Walnut Tree Leaves
In the fall, all walnut trees have feather-like pinnate leaves that turn yellow or brown. On each blade, there are generally two to nine pairings of leaflets, with one additional leaf at the tip. In the autumn, the leaves turn yellow or brown. A distinct spicy citrus aroma is released when crushing walnut leaves.
Butternut (white walnut) tree has oblong-lanceolate leaves, which are comparable to those of the three common walnut tree species. In comparison, English and black walnut leaves have shorter, more rounded leaves.
The leaves of black walnut have a tiny terminalleaflet that can be missing, which distinguishes it from other species. Nonetheless, a huge leaflet is always present at the tip of butternut and English walnut trees.
Walnut Tree Nuts
On the tree (left image), immature walnuts look like green tennis balls. Walnut shells (or drupes) are visible in the right photograph, hidden inside their green husk. Walnut fruits are little green balls that grow on trees. The nutshell and kernel or nut are both surrounded by the outer green layer. Walnut tree nuts have two halves with a ragged exterior and a papery coating.
Walnut Tree Identification
The bark, leaves, and nuts of walnut trees can all be used to identify species. Light gray to dark brown is their bark color. Several species have bigger leaves than others, while walnut leaves are pinnate. Walnut nuts are similar in appearance, however the species’ flavor and texture might vary.
Walnut tree bark The trunks are usually scored with deep vertical crevasses. Brown to dark gray walnut bark with diamond-shaped patterns is available. The bark of walnut trees is less rough and lighter in several varieties.
Walnut tree leaves Pinnately arranged leaves are found on these species. A single leaf occurs at the end of the twig in most walnut leaves. The leaves have between 5 and 25 leaflets, with the largest ones in the middle. In the autumn, all walnut tree leaves turn brown or yellow.
Walnut tree nuts Little round or oval green spheres appear to be growing on the tree. A hard-brown shell protects the walnut nut or seed. Walnuts have a earthy to mild and sweet flavor.
Types of Walnut Trees (With Pictures)
Black walnut, English walnut, and butternut or white walnut are the most common types of walnuts. Nonetheless, South America, Asia, and southeastern Europe are home to other walnut types. The wood from black walnuts and English walnuts is well-known.
The sweetest nuts are those from the English walnut tree. The most common types of walnut trees have identifying characteristics that are listed below.
Black Walnut (Juglans nigra)
The black walnut tree grows to between 75 and 130 feet (22 and 40 meters) tall, with deeply furrowed bark. In USDA zones 4 – 9, the deciduous walnut tree is found throughout North America’s eastern region. The growth of black walnut trees is medium, and they prefer to live in sunny locales.
The eastern American black walnut, also known as American walnut, is another name for black walnuts. They grow in forests and woodlands and may be found from southern Ontario to northern Florida. Walnut trees may reach a height of 130 years. The black walnut tree bears big pinnate leaves with a wide, rounded crown. The massive nut-bearing tree may have a spread of several meters and a height of several meters.
The pungent citrus-like odor of black walnut tree leaves and branches. Black walnut trees bear flowers in both sexes. Long catkins dangle from the limbs of male walnuts. At the ends of short spikes, female walnuts produce little groups of flowers.
The black walnut tree produces globe-shaped green fruits that resemble green balls after it has finished blooming. They are 2″ (5 cm) in diameter. The black walnuts appear to be rough green spheres after they have just fallen from the tree. Their husk darkens from green to a deeply brown (or black) color as they grow on the ground. The hard shell that protects the edible nut is found inside the tough husk.
Black walnut trees also release hazardous chemicals into the soil, which is another identifying trait. Since plants don’t grow within a 50 to 80 foot (15 – 24 m) radius of the tree, you can tell black walnut trees.
Walnut tree bark: The bark of the black walnut tree is black with deep diamond-shaped ridges. During the winter, black walnut trees with their distinct bark pattern are easy to recognize.
Walnut tree leaves: The pinnately compound leaves of black walnuts have 15 to 23 leaflets each. 3″ to 4″ (7–10 cm) long leaflets are distributed. The ovate, lanceolate shape of the leaves has a somewhat serrated border. In the fall, the leaves turn yellow.
Green balls on the tree, similar to the green tree leaves, appear brown when black walnuts are ripe.
Butternut or White Walnut (Juglans cinerea)
Butternut or white walnut trees have smooth gray bark and produce delicious nuts. They grow up to 66 feet (20 meters) tall. Only that they are smaller and have smoother bark, butternut trees resemble black walnut trees. Walnuts, especially white walnuts, thrive in zones 3 to 7.
To distinguish butternut trees from other walnut types, there are a few identifying characteristics. Butternut trees, for example, produce fruits that are oval rather than spherical. The leaflets on their leaves are less likely to be present. The heat tolerance of white walnut trees is inferior to that of black walnut trees.
Butternut (white) walnuts have a buttery flavor, unlike the earthy flavor of black walnuts. They have an oval shape and green husk. Toxic chemicals are also released by white walnut trees in the soil. This, on the other hand, is not as potent as black walnut and has a lesser impact on neighboring plants.
Walnut tree bark: When the tree is young, the bark of a butternut tree is gray and smooth, and as it matures, the bark becomes rough and fissured.
Walnut tree leaves: Butternut leaves are oblong, lanceolate, and vary in length from 5 to 12 inches (12 to 30 cm). The leaves have a pointed tip and are serrated along the edges. Leaf stems always have a single big tip or terminal leaf.
English Walnut (Juglans regia)
When young, the bark of the English walnut (Juglans regia) tree is smooth and olive-colored, but as it grows older, it becomes deeply fissured and gray. With a crown of pinnate leaves that is roughly 65 feet (20 meters) wide, English walnuts grow to roughly 65 feet (20 meters).
The primary source of walnuts sold in today’s markets is American walnut trees. Persian walnut, Madeira walnut, and Carpathian walnut are all names for the English walnut tree. The walnut tree’s natural environment in southern Europe is reflected in its common names. Full sun and zones 5 to 9 are ideal for common walnut trees.
English walnuts, like black walnut trees, create spherical drupes with delicious seeds. When they’re on the tree, English walnuts (Juglans regia) appear to be green tennis balls. But, when they fall to the ground, their green rough husks turn black (nearly black) in color after a few seconds.
English walnuts have a mild and pleasant flavor, according to some. Pickled walnuts are a specialty of some regions of Europe, and you can also eat the whole nut.
Walnut tree bark: The bark of English walnut trees is deep and fissured, ranging from gray to brown.
Walnut tree leaves: Pinnate leaves with 5 to 9 leaflets and a single blade at the tip characterize the English walnut tree. 4 to 7 inches (10 to 18 cm) long are individual leaflets. English walnut trees have fewer leaflets when compared to butternut and black walnuts.
California Black Walnut (Juglans californica)
The California black walnut tree is a uncommon big multi-stemmed shrub or tiny tree with a single stem. In warm climates and full sun, California walnuts grow to between 20 and 50 feet (6 – 15 meters) tall. In zones 7 through 10, these little walnut trees develop.
Walnut tree bark: The bark on California black walnut trees is a dark gray color and is thick. The deep furrows running up and down the trunk distinguish the bark.
Walnut tree leaves: The margins of California black walnut trees are serrated, but not heavily. Pinnate leaves have 11 to 19 elongated leaflets.
Northern California Black Walnut (Juglans hindsii)
The walnut tree has a solitary stem and grows up to 60 feet (18 meters) tall in Northern California. The tree is mostly used in the lumber industry and is also known as Hinds’ black walnut or claro walnut. In zones 8 and 9, these black walnut trees thrive in arid, bright environments.
Walnut tree bark: The bark on the trunks of northern California black walnuts is dark gray, with occasional fissuring.
Walnut tree leaves: The leaves of the Hinds black walnut are roughly 12 inches (30 cm) long. Blades range in length from 13 to 21 leaflets, each up to 5 inches (12 cm) long. The leaves have a few little hair tufts.
Arizona Black Walnut (Juglans major)
Arizona black walnut is a little walnut tree that may grow up to 50 feet (15 meters) tall. The long stem supports a 65-foot-wide (20-meter) spreading crown. Little edible nuts are produced by Arizona walnut trees.
Walnut tree bark: Gray-brown bark with deep furrows and flat-topped ridges characterize Arizona black walnuts.
Walnut tree leaves: Arizona walnut trees have pinnately complex leaves, like other species of walnuts. The pointed and oblong leaves have between 9 and 15 leaflets each.
Fruits of the Arizona black walnut tree are green balls. The tree’s leaves are green in color.
Andean Walnut (Juglans neotropica)
The genus Juglans includes slow-growing trees such as the Andean walnut tree. In Peru, Columbia, and Ecuador’s highlands, Andean walnuts grow to 131 feet (40 meters) tall. The high-quality red-colored timber of these tropical walnut trees is prized. Columbian walnut, Ecuadorian walnut, and Cedro negro are some other names for this walnut species.
Walnut tree bark: The reddish-brown bark of the Andean walnut tree features deep, lengthy seams.
Walnut tree leaves: Long leaves up to 15 inches (40 cm) are seen on the tropical walnut. The pointed oval leaves that make up the walnut foliage.
Japanese Walnut (Juglans ailantifolia)
Because of their leaf shape and buttery nuts, Japanese walnut trees are similar to butternut trees. These light gray barked Asian walnut trees grow up to 66 feet (20 meters). The walnuts’ hearts are shaped rather than spherical or ovoid, which is an unusual characteristic.
Walnut tree bark: The bark of Japanese walnuts is light grey, with network patterns in the grooves.
Walnut tree leaves: Leaves on Japanese walnut trees are 2 feet (60 cm) broad and feature 11–17 large leaflets. Up to 6 inches (16 cm) of leaflet may be included.
Little Walnut (Juglans microcarpa)
This small walnut species is a big tree-like shrub that includes little walnut leaves and bark. The Texas walnut tree may reach heights of up to 30 feet (9 meters). Zone 7 through 9 is where the sun-loving walnut shrub may be found. The timber and fruit are both small, and they are of no value.
Walnut tree bark: The bark of the little walnut tree ranges in color from gray to dark brown, with faint grooves.
Walnut tree leaves: Between 7 and 25 tiny leaflets with smooth or slightly serrated borders cover the leaves of the little Texas walnut tree.
Manchurian Walnut (Juglans mandshurica)
One of the coldest hardiest walnut trees is the Manchurian walnut tree, which originates from East Asia. Since their nuts are tiny and difficult to extract, tall walnut trees that are rapidly growing may be used as decorative trees. In zones 2 through 8, Manchurian walnuts are cold hardy and can withstand temperatures as low as -49°F (-45°C).
Walnut tree bark: The bark of the Manchurian walnut tree is fissured, as it is on most walnut tree species.
Walnut tree leaves: The Manchurian walnut tree’s pinnately complex leaves have a single terminal leaf and 3 to 9 pairs of leaflets.
Juglans mandshurica ‘sachalinensis’ Manchurian walnut leaves