Black Walnut Tree Identification Guide: Leaves, Bark, Value Calculator, Pros and Cons

A Black Walnut tree with bright yellow-green leaves against a clear blue sky, in an oval frame set on a green background.

The black walnut tree is one of the largest trees in the country, native to the North Eastern regions of the United States, and famous for its enormous size and deliciously edible nuts.

In fact, if you’ve ever tried to harvest black walnuts, you may have had a difficult time (if you didn’t know how to wait)!

But, the Black Walnut tree has more to offer than just it’s fruit, this tree is an integral part of North American forests, growing for decades and impacting the ecosystem where it flourishes in important ways.

This complete Black Walnut Tree identification guide explains everything you ever wanted to know about growing and maintaining this tree, the pros and cons of having one nearby, and how to figure the value of the timber when the tree needs to be harvested.

Eastern American Black Walnut, Black Walnut

(Juglans nigra)

Black Walnut tree in an oval frame on green background.
  • Family: Juglandaceae
  • Genus: Juglans
  • Leaf: Pinnate with serrated edges, dark green
  • Bark: Has diamond shape grooves, grayish-black
  • Seed: Tiny and hard
  • Blossoms: Male: Up to 4 inches long catkins, Female: Clustered at the tip of a stem
  • Fruit: 3-Layered round fruit
  • Native Habitat: North America
  • Height: From 50 to 75 feet
  • Canopy: Up to 75 feet
  • Type: Deciduous

IUCN Red List of Threatened Species Ranking

Least Concern


Image Credit: User:MONGO19

Black Walnut Tree Identification

Various types of trees grow in all parts of the country, and it helps to know how to identify black walnut from the rest.

Fortunately, the black walnut is specific, and can be identified throughout the year by its bark.

Photo of a black waltnut tree.

(Image: UNH Extension16)

The Black walnut tree is a gigantic species with a straight, rigid trunk and a round crown.6 It produces edible nuts making it a wildlife attraction, and it features massive feathery compound leaves with an alternate pattern reaching up to 24 inches.

It has a dark grayish or black bark with ridges running through vertically in diamond shape patterns. The black walnut tree flowers in April-May, and the green, round and tasty fruits show in September- October.

If you’ve ever been a child near one, you know that the greenish outer shell of the walnut hides a dark pulpy substance that will stain fingers, clothes, and just about anything!

What Does a Black Walnut Tree Look Like?

The black walnut tree species is massive, with a ridged trunk and a rounded canopy.

Its bark is dark with diamond-shaped vertical ridges, and its leaves are compounded with several leaflets attached.

Black Walnut Tree Identification Chart Showing Black Walnut tree leaves, black walnut tree bark, black walnut tree seeds, black walnut tree fruit for (Juglans Nigra) in circle frames on a green background.

However, its most noticeable feature is the green spherical nuts appearing in September-October, measuring 1-3 inches wide.

Facts About the Black Walnut Tree (Juglans Nigra)

The US is home to hundreds of different kinds of trees, but the black walnut stands out. Below are some facts you should know about it.

  • It is scientifically known as Juglans nigra
  • It thrives in 4-10 USDA zones1
  • It can grow 12-30 inches annually based on prevailing conditions
  • Its nuts appear as early as five years, but abundant production starts at ten years
  • The tree produces a toxic chemical called the juglone, which inhibits nearby plants’ growth
  • It is critical for the ecosystem, given that nuts are a favorite food for wildlife
  • Given its high toxicity, the tree is not ideal for interaction with horses or use as bedding

Features of the Black Walnut Tree Leaves

The leaves are the most common ways to identify a tree, and you can spot a black walnut tree by its pinnate compound fronds that usually have 15-23 leaflets.7

Each connected leaf measures 5-10 cm and is thin and lance-shaped with fine margin serrations.

Close up photo of black walnut leaf

(Image: Kristjan17)

The whole leaf can grow as big as 30-60 cm, and the leaflets turn yellow during fall when the temperatures start plummeting and are the first to discolor in autumn.

Also note that the leaves don’t stay long on the tree, dropping early and showing up late, especially after infection by the walnut anthracnose.8

Features of the Black Walnut Tree Bark

The bark is another way to identify a black walnut besides the leaves.9 It has a long, thick, dark grayish-black bark that grows to have deep thin vertical ridges throughout its length.

If you carefully look at it, you will notice a particular diamond shape pattern running its height. Depending on the tree, its twigs and branches take a coppery brown or black shade.

When mature, a black walnut’s trunk can grow to a massive 2 meters in diameter, making it perfect for lumbers.

Black Walnut Tree Fruit Identification

The fruits appear between September and October and grow as pairs or singles.10

They are round and green, often growing to 1-3 inches wide, covering hard, black nuts inside.

Photo of the black walnut tree fruit and leaves.

(Image: Hans18)

Animals like rodents and squirrels are attracted to the sweet oily kernel and tough nuts making the tree ideal for ecology.

They are also a common ingredient for cookies and pies, and you can incorporate them in your meals or eat them whole.

How To Identify a Black Walnut Tree Seed

Removing the walnut seed from its rigid enclosure or the nut’s shell can be challenging, and you will need special equipment.11

The tasty nuts lie inside a rugged ball-like body with ridges around it, and you must break it to expose them.

The seeds look like typical nuts, fleshy and delicious, and you can grow another black walnut from them as soon as you test that they are viable.

They will mature as the tree grows, and you can harvest them during fall.3

Black Walnut Tree Nuts Identification

Black nuts are one of the surest ways to tell apart a black walnut. They drop soon after the leaves from September to October, and the yellow-green outer cover turns black later on when on the ground.

The female parts of the tree turn into these ball-sized nuts, which feature a green husk outside and a shriveled dark look. When mature, the nut can grow to the size of a golf or ping-pong ball, and you can identify one from its rough exterior.

If growing one at home for your landscaping needs or nut production, the seed may appear at 4-6 years.12 However, those growing in the wild can take up to 30 years before the nuts appear.

How To Grow a Black Walnut Tree From Seed

You can propagate black walnut trees from the nuts when they start dropping. You first collect them from the tree, avoiding the fallen ones and removing the skins, and test their viability or potential to grow by confirming that they sink in water.

Black Walnut tree growth chart on a line graph with Black Walnut tree age on the x-axis and Black Walnut tree height on the y-axis.

Besides the test, it is also critical that they undergo cold stratification and storage to germinate before you plant them, and you can do it in simple steps. First, find a zip-lock bag and sand mixed with water.

Next, place the walnuts in the middle of the mixture and store the bag in the fridge until planting. You can then dig them 1-2 inches deep in the ground and water and care for them until the tree sprouts in spring.

Which Plants Don’t Grow Well Near Black Walnut Trees?

The black walnut is allelopathic, which affects the growth of surrounding tree species by releasing a toxic chemical from its roots. If planting one in your home, it is crucial to know that vegetables like tomatoes, potatoes, cabbages, and peppers cannot grow close to them.

Flowers like petunias, peonies, lilac, yew, and azalea shrubs are also susceptible to toxic juglone. Black walnut is also dangerous to pine, birch, and apple trees. If affected, your plants will show signs of yellowing and wilting and eventually die.

Which Plants Look Like Black Walnut Trees?

It is easy to confuse black walnuts with other trees since they are hardy and can grow anywhere.

Examples of plants that look similar to black walnut are the tree of heaven and the sumac, but you can distinguish them by their unique features.

For instance, the tree of heaven emits a distinctive foul smell, and its leaves are not serrated, while the sumac’s leaves turn bright red during fall and have red flowers.

Where Does Black Walnut Grow?

The black walnut is famous for its resilience and hardiness, able to grow wherever you plant it. This feature makes it ideal for reforestation or forest rehabilitation in formerly bare land.

Animals tend to carry and bury the nuts, which later sprout; therefore, one can grow without you planting it. If the conditions are favorable, the nuts undergo stratification during the winter after being buried by squirrels in the fall, germinating, and sprouting.

How Black Walnut Is Beneficial for Wildlife

If you are conscious of the environment, you can buy carbon offset credits or engage in tree planting. You can also attract animals by planting the black walnut tree, which they love for its tasty nuts. It provides food and shelter for animals in the wild, and they will be naturally drawn to it.

Its primary benefit is providing nuts to animals like squirrels, which collect and bury them when preparing for the winter. The Eastern Fox species, for instance, obtain about 10% of its diet from these nuts.2

The massive tree is also a suitable host for luna and regal moths, which are enormous insects native to northern parts of the US. Additionally, it is a perfect perch for the Eastern Screech owl.

Black Walnut Tree Pros and Cons

Here are the pros of the black walnut tree:

It Is a Great Shade Tree: Pro

There are several benefits of planting trees, and people opt for the black walnut tree because of its massive height and fast growth rate. You can use it for shade or landscaping but be careful that it is not too close to the house, or the nuts will block your gutters.

A person stands under the expansive canopy of a black walnut tree, surrounded by a lush green park, with a gravel pathway curving around the tree's massive trunk.

(Image: Horst J. Meuter20)

Its shape, height, and general look make it perfect for beautifying your home, especially when you grow it in an open space far from other trees.

It Produces Edible Nuts: Pro and Con

Walnut trees are a favorite for animals and humans thanks to their tasty nuts, and you can have a constant supply when growing one in your yard.

They are nutritious, and you can eat them whole or use them as ingredients.

However, they can make walking in the yard after they drop a little like walking in a field of marbles, so the clean up each year can be bothersome.

It Is Famous for Its Hardwood

Lumbers from black walnuts are impressive thanks to their closed grain, making them ideal for furniture making and constructing other wooden art projects.

When the tree is older, it can be harvested for safety and the wood used for all sorts of furnishings and other artistic pieces.

As long as it isn’t burned, the wood will continue to sequester any emissions stored in it for many decades.

It Needs Heavy Cleanup

Walnut trees produce nuts annually, which often means they will litter your compound and sidewalks.

Squirrels can pick and bury some, but they are generally tasking to deal with during the drop season.

Moreover, they can be difficult to harvest if you don’t allow the husk to fully rotten…using a hammer won’t break them open, but of course, squirrels have no problem.

They Cause Juglone Poisoning

The “dark side” of black walnuts is that they produce a toxic chemical called juglone, which is lethal to plants and some animals.13

It is present on the leaves, bark, and roots and hinders the growth of other species nearby. It can also cause skin irritation to susceptible people.

Which Parts of the Black Walnut Tree Are Toxic?

Unfortunately, the whole black walnut tree is toxic, naturally producing juglone from each part. However, it is mainly from the roots, nut shells, and buds, while the leaves, stems, and twigs have the lowest concentration.

The leaves will also produce chemicals when they fall off the tree, similar to the roots, even after cutting down the tree. The root zone is responsible for most chemical releases, stretching up to 60 feet wide.

Uses of The Black Walnut Tree

The black walnut tree boasts several uses in the medical world and at home. Below are some common ways to use its nuts.

You Can Eat Them

Like other edible nuts, black walnut is highly nutritious and is widely regarded as a superfood.

It contains a high protein content of 7 grams in a serving and features high levels of Omega-3 and more nutrients.

They Have Medicinal Properties

Physicians globally hail black walnut as an effective medicine for various conditions, including cancer and worm infestation.

However, you should be careful when handling it, and it is best to consult a doctor before using it for any ailment.

They Are Natural Disinfectants

You can dry walnut hulls and soak them in alcohol and use the mixture on cuts and bruises as a disinfectant for your first aid needs.

You Can Use Them as Homemade Dye

The black hulls make excellent dye for leather and fabrics, and you can make a blend at home for DIY dyeing or natural ink.

What Is the Black Walnut Tree Value?

Apart from beautification, you can also grow trees as an investment, considering their timber’s value. Planting some means you could make a lot of money by selling them, but the key is to know whether you are getting your tree’s worth.

Like other products, the walnut tree’s value depends on the market’s forces of supply and demand, such that you will get more from it if the demand is higher. Luckily, the walnut tree’s worth remains high, especially in countries like China.

Currently, the tree’s value stands at about $5- $10 per foot (board), although it can go higher. The timber is perfect for furniture production and making cabinets and flooring.

How Does a Black Walnut Tree Value Calculator Work?

You need a Black Walnut Tree value calculator to help you calculate how much your tree is worth; you may want to sell yours or seek compensation after someone wrongfully cut it down. You only need a few steps to determine roughly how much your tree costs.

First, you enter the tree’s circumference, then its height, and use the details to calculate the value in dollars. The goal is to make correct measurements to find more accurate estimations. All you need to enter is the tree type, height, circumference, and the basic value from special tables.5

The equation to follow is:

Tree value= height * circumference * basic value

In this case, the circumference is in inches, height in feet, and tree value in dollars.

What Are the Factors Affecting Black Walnut Tree Value?

Several factors come into play when determining your black walnut tree value, but most importantly, it depends on its size, diameter, and height;14 gigantic trees will fetch more in the market than smaller ones.

The veneer rating is another crucial factor because it decides the wood quality. The grading system relies on the wood’s condition, whether it has damages, knots, or other imperfections. Your tree will be high quality if it is flawless and free of these blemishes.

The wood color is another determinant because the darker it is, the higher the quality. Besides the tree’s features, whoever you want to sell to can also impact the cost; buyers often consider the cultivation size or nearness to the factory.

CO2 Absorption Properties of a Black Walnut

One of the primary advantages of growing trees is that they are natural air purifiers and effectively aid in the efforts to manage climate change. A key question is how much carbon does a tree capture, but various factors come to play to determine the rate.

Trees are natural carbon reservoirs as they capture more CO2 from the atmosphere as they grow, but the amount varies based on the tree species, size, age, and other factors like its location. Experts estimate that the black walnut reduces carbon levels in the air by up to 34 pounds annually.

How To Tell If a Black Walnut Is Dead

An admirable feature of black walnuts is that it is tough, reaching over a hundred feet and living for more than 100 years. However, it will eventually die like any other living thing from old age if not from pests and diseases.

The only challenge is not knowing how to tell when yours has died. A straightforward way to know is by checking for new growth during spring. If there are no fresh leaves, it is likely dead, but any change means it is still alive.

Alternatively, if you can’t wait for spring, you can check whether the twigs bend easily or if the layer underneath a peeling bark is green; otherwise, your tree is dead.4

Harvesting and Eating Black Walnuts

Picking up the nuts is the fun part of cultivating black walnuts. Using protective gloves, you can check that the husks dent when you press them, but if you wait too long, the husks will have darkened and will have a bitter taste.

The best time to harvest is from late September to October, and you should know how to process them in preparation for consumption. You may need the proper equipment to break into the hard shell; you can use a hammer, knife, or cover and drive over them to crush them easily.

Afterward, remove the hulls, clean the nuts, then dry them, leaving them on a flat surface for some time. These nuts can stay fresh under proper storage for up to one year.

Caring For Black Walnut Trees

If you have a Black Walnut tree that you want to maintain (or you’ve planted a sapling), care for it like other large hardwood trees:

  • Make sure there is adequate sunlight and water
  • Observe any signs of diseases and pests and address them quickly
  • Clear the ground each year of rotted nuts

How To Get Rid of Black Walnut

Black walnut’s primary downside is its allelopathy since it is among the Juglandaceae species.15 It suppresses the growth of other plants around it by releasing juglone, a toxic chemical present in its leaves, twigs, roots, and bark.

If you don’t want it to affect nearby plants and want to eliminate it, you can pluck it from its roots carefully to capture the entire root system. However, if it is a massive mature tree, you can cut it down and cover the stump with chemicals to prevent it from sprouting afresh.

The aim is to speed up the stump’s decomposition process or use a glyphosate herbicide. Alternatively, you will be safer seeking an arborist’s services at a small fee.

The black walnut is famous for its tasty nuts, which are attractive to animals like squirrels and mice. Given its massive size and fast growth rate, you can plant one in your yard for a steady supply or use it for landscaping.

It is also known for its medicinal properties, healing worms, managing cancer, and serving as a natural disinfectant. However, its main downside is that it produces juglone, a toxic chemical that suppresses the growth of other plants around.

To be safe, it is best to grow the black walnut tree away from other trees and vegetables and be careful that it is not near your house, or the falling nuts will be a nuisance.

Frequently Asked Questions About Black Walnut Tree

Which Pests Affect Black Walnut Tree Growth?

The most common pest to watch out for is the “Thousand Canker Disease,” which infects mature trees. It is caused by the Pityophthorus juglandis beetle that eats away at the tree, creating a perfect environment for the cankers to attack.


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