|Mature Height||60 to 100 feet|
|Best Habitat||Deep, moist soil with full sunlight
|Uses||Food, furniture, dye|
The Walnut tree is among the most versatile hardwoods on the planet. In addition to yielding exceptional tasting nuts, its timber is treasured by carpenters and sculptors alike. The Walnut tree's wide array of uses also makes it a popular pick for homeowners looking to decorate their properties with a practical and profitable specimen.
Appearance of the Tree
Walnut trees are hard to miss. A mature tree can tower up to 100 feet tall with a leaf canopy of more than 40 feet wide, though most average between 60 and 70 feet. The tree is also very durable, with some living 200 years.
In addition to its formidable physical presence and longevity, the Walnut tree has a number of other notable characteristics, including:
- Leaves: Walnut leaves are compound, meaning they are composed of a main stem and numerous separate leaflets. Up to 23 leaflets can be found on a single leaf. The long leaves remain green until autumn when they turn yellow and fall off the tree.
- Fruits: The tree's fruit is by far its most noteworthy trait. The walnut is housed in a hard, round, brown shell which features a host of grooves and furrows. The shell of the Black Walnut is green, though it turns blackish as the nut ripens.
- Flowers: The Walnut tree's flower is a yellowish-green drooping catkin which covers the tree in the spring.
- Bark: The bark of a mature Walnut tree sports deep ridges which form a diamond-like pattern. The bark's color ranges from a rich brown to dark gray.
Walnut trees are also fast growers with some shooting up to 25 feet in less than 10 years.
Walnut Tree Types
There are nearly two-dozen different types of Walnut trees in the world, though most are native to the United States. Among the most popular are:
- Black Walnut: The tallest of all Walnut trees, the Black Walnut can grow as high as 100 feet. The tree's fruit grows in clusters and falls in autumn. The Black Walnut's shell is unique in that it contains a dark brown dye that will stain any item it comes in contact with.
- Butternut: This popular tree is also known as the White Walnut. It grows primarily in the northeastern portion of the United States and is shorter than its cousins, typically topping out at 60 feet. The tree's oval nuts have high oil content and are featured in a number of food products.
- Arizona Walnut: The tree grows in the canyons, desert and mountainous areas of Arizona through western parts of Texas. While it can reach heights of 50-plus feet it is generally classified as a shrub that stands roughly 20 feet tall. The tree produces small nuts with thin, hairy husks.
Other types of Walnut tree include:
- Japanese Walnut
- Bolivian Walnut
- Southern California Walnut
- Northern California Walnut
- West Indian Walnut
- Manchurian Walnut
- Andean Walnut
- English Walnut
- Little Walnut
Walnut trees may vary in size; however, they are harvested the same way by hitting the ends of the branches with a solid object. Knocking off both the nuts and the branch tips encourages new growth.
Where the Walnut Grows
Walnut trees are predominantly grown in North America with California being the largest purveyor of the trees. The trees also prosper in other parts of the world, such as:
Walnut trees are thirsty specimens. They thrive in deep, moist soil and full sunlight. Younger trees need more water than mature ones, though both can benefit from mulch and a weed-free environment.
The handsome tree is a joy for landscapers to work with. In addition to being attractive, Walnut trees are also prized for providing a ton of shade. That shade is a bonus for wildlife enthusiasts, who often grow Walnut trees on their properties to attract birds, squirrels and deer.
Other popular uses for the Walnut tree are:
- Food: Walnuts are one of the healthiest nuts on earth. They contain high levels of omega-3 fatty acids, iron, protein and antioxidants, which help stave off colds and other respiratory illnesses. In addition to their nutritional value, the nuts are delicious when added to brownies, cakes, breads, ice cream and tea. They are also popular as a topping for salads, yogurt and fruit.
- Wood: Walnut wood is highly valued due to its durability and color. The timber is used to make chairs, tables, floors and cabinets. The tree's wood is also used to craft music boxes, jewelry cases and caskets.
- Dye: Black Walnut trees are especially prized for their natural dyes. The built-in ink can be extracted from the tree and used to color fabrics, paper and hair.
In addition to these uses, walnut shells can be ground and used as a cleaning agent for jet engines and as filler for dynamite.
In Ancient Greece, the walnut was referred to as "The Nut of Jupiter," as its vast array of attributes made it worthy of the gods. Today, the nuts are appreciated by a host of consumers, many of which may not be aware of these interesting walnut facts:
- Centuries ago, Native Americans would extract oil from the Walnut tree to cook corn and beans.
- It takes 10 growing seasons for most trees to produce mature fruit.
- California is home to more than 125,000 acres of Walnut trees.
- Picked walnuts should be stored in cool, dark environments.
- A handful of black walnuts contain more protein than two slices of bacon.
- Walnuts are the number one substitute for pecans in baking recipes.
While the tree's nuts and wood may be hardy, the tree is not invincible. Walnut trees are susceptible to a number of diseases, such as:
- Walnut Blight: The bacterial disease affects the tree's nuts and typically occurs during extensive periods of wet and cool weather. The disease creates black spots on the tree's leaves and can create holes and spots on the nut's husks.
- Walnut Leaf Blotch: This fungus can spread extensively over a tree in a short period of time, especially during wet weather. The disease is spread by rain droplets dripping off infected parts of the tree. Symptoms of an infected tree include brownish blotches that appear on leaves and falling fruit.
- Honey Fungus: The fungus turns leaves yellow and forces them to droop and fall well before autumn. The disease travels from the roots and can spread throughout the tree, eventually rotting it to its core.
Other less common Walnut tree diseases include crown gall, blackline, downy spot, and nectria. In addition, insects, such as codling moth, red spider mite, walnut weevil and husk flies also prey on Walnut trees.
Walnut trees don't require an extensive amount of care to grow. However, your tree will benefit if you follow these simple tips:
- Plant the tree in deep, well-drained soil.
- Water Walnut trees regularly.
- Keep Walnut trees away from shorter plants that need sunlight to grow.
- Walnut trees should be placed at least 50 feet apart from one another and away from buildings, as their large canopies can interfere with power lines.
- Black Walnut trees should not be planted near other vegetation, as their dye-like substance can be toxic to other plants.
- Harvesting of nuts is critical, especially if you don't want to deal with having to pick-up fallen nuts.
Finally, it's important to clean-up around the perimeter of a Walnut tree prior to mowing grass, as the hard nuts can potentially cause damage to you and your mower if the net gets caught in the machine's blades.