The black walnut tree (Juglans nigra) is one of North America’s most valuable and beautiful native trees, but it does have a “dark side.” Here’s what you should know before planting a black walnut in your yard—and how to harvest and eat the tasty black walnuts too!
Facts About the Black Walnut Tree
The easily worked, close-grained wood of the black walnut has long been prized by cabinet- and furniture-makers for its attractive color and exceptional durability. Black walnut logs are in such demand for veneer that “walnut rustlers” have made off with trees in the dead of night and even used helicopters in their operations.
Early settlers discovered black walnuts growing in mixed forests from Canada to northern Florida and west to the Great Plains. They found that their rich-brown heartwood was exceptionally resistant to decay and used it for fence posts, poles, shingles, and sills.
When surrounded by other trees in the forest, black walnuts grow straight and tall with few, if any, lower branches.
When planted in the open, the tree will branch out closer to the ground, developing a spreading shape that makes it easier to harvest its sweet, round, 2- to 3-inch nuts.
Settlers snacked on the nutritious walnuts out of hand, added them to soups and stews, and ground them into a meal for baking; the hard shells provided a perfect package for storing the nuts over winter.
What Is Juglone?
Although the black walnut has many uses and benefits, the tree does come with a caveat: the black walnut’s roots, which may extend 50 feet or more from the trunk, exude a natural herbicide known as juglone. This substance is also found in the tree’s leaves and fruit husks.
Juglone does serve a purpose, though. It inhibits many plants’ growth under and around the tree, thereby limiting the tree’s competition and leaving more water and nutrients for itself.
Tomatoes, potatoes, apples, pears, berries, and some landscape plants such as rhododendrons, azaleas, and lilacs may be killed or stunted if grown close to black walnut roots or within the tree’s drip line (i.e., under the tree’s canopy). Plan your landscaping accordingly!
Juglone Plant Susceptibility Chart
Highly Susceptible (Avoid Planting Near Black Walnut)
Tolerant (Safe to Plant Near Black Walnut)
Tomato
Corn
Potato
Beans
Eggplant
Carrots
Peppers
Beets
Apple Trees
Onions
Pear Trees
Cherry Trees (some varieties)
Blueberries
Black Raspberry
Rhododendrons
Pawpaw Tree
Azaleas
Red Maple
Lilacs
Hickory
Mountain Laurel
Oak (most species)
Hydrangea
Dogwood
A Great Shade Tree
Black walnuts make great shade trees for larger properties. They commonly grow to 50 feet or taller and about as wide, but specimens of more than 100 feet have been recorded.
Black walnut’s large, fernlike foliage provides light, airy shade for those grasses and ground covers unaffected by juglone. The leaves turn bright yellow in autumn, contrasting nicely with the tree’s rugged, dark bark.
Black walnuts require deep, fertile soil with a near-neutral or slightly acidic pH. They are pretty much disease-free and are threatened by a few pests.
How to Harvest Black Walnuts
Thud! Thud! Most walnut tree owners have a love/hate relationship because of the fruit the tree drops in late summer through October. The fruit is quite heavy, the size of a baseball, and lime green in color. It makes quite a mess and can be viewed as a nuisance.
Walnut tree owners will spend hours picking up the fruit in some years. If you don’t remove the nuts, you’ll trip over them in the dark for the rest of the year (while they rot and mold on your lawn). Hire the kid down the street to pick up those dropped walnuts (just be careful not to pay per nut—you’ll go broke)!
Photo Credit: John A. Anderson
If you’re willing to crack the outer shell, the “meat” inside is edible, as the squirrels will attest; squirrels have little problem chewing through the shells. (Note: Black walnuts are different from English walnuts, which are more commonly sold in stores and shown in the photo above.)
The sweet, earthy nutmeat inside is well worth the effort. Your grandparents may have harvested walnuts, which can be eaten raw or added to baking (cookies and bars). They can also be used as toppings on ice cream and cakes, enjoyed as a sweetened candy nut, or ground into a meal for a unique flour.
How to Harvest Black Walnuts
To harvest, collect the nuts as soon as possible to avoid mold and remove the husks immediately.
Wear gloves as the husks stain your hands (and anything they touch). If the nut is too hard, wait a few days, and it will brown and soften up.)
To remove the husk, you can step on them gently with an old pair of shoes. Hose down the nuts in a large bucket to remove any remaining husk.
Dry the walnuts for a couple of weeks on a screen, drying rack, or in a hanging mesh bag. You can store them unshelled for up to a year.
Crack the shell with a hammer to get to the nut meat. (Strike at a 90-degree angle to the seam until the nut cracks). Use pliers to easily clip away the shell to release the nutmeat.
Allow the freshly removed nutmeat to dry for a day before storing.
Do you have a black walnut tree? Please share your comments, questions, and advice!
George and Becky Lohmiller shared their gardening knowledge and enthusiasm with Almanac readers for more than 15 years, writing Farmer’s Calendar essays and gardening articles in previous editions of The Old Farmer’s Almanac.
The image credited to John Anderson is not correct. While the nuts to the left are black walnuts, the shelled nuts to the right are English Walnuts. Black walnut meat looks quite different. And I assure you, no one ever ate Black Walnuts “out of hand” You need a hammer to crack the shells.
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<a title="View user profile." href="/author/editors">The Editors</a>Fri, 03/27/2020 - 09:08
Hi, John: Thank you so much for taking the time to make this article better. We have now made note in the text about the English walnuts. With regard to "out of hand," this just means "fresh from the tree (or ground)" rather than, say, cooked. So you would just assume that anyone eating black walnuts out of hand would also need a rock or two or an axe head or whatever to aid in the cracking. Thanks again!
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<span>Maria D Lemos</span>Fri, 02/21/2020 - 11:31
Are the fruit harmfull to dogs we have a tree in big bear CA
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<a title="View user profile." href="/author/editors">The Editors</a>Fri, 03/27/2020 - 09:04
Hi, Maria: It is not so much black walnuts themselves that are harmful to dogs, but instead a particular mold that can grow on the shells as they rest on the ground. It is also believed that black walnut wood (e.g., sticks) may be harmful, too, so the bottom line is that black walnuts and dogs do not mix. Thanks for asking!
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<span>Bev Ward</span>Sun, 02/09/2020 - 16:16
After extracting the 'meat'(kernel) from the shell of the Black Walnut, there is alot of debris(from the shell) mixed in with the precious 'meat'. Previously, visually. . .I carefully removed 3-5 small slivers of shell from about 1/2 cup of Black Walnut 'meat'. An old Cherokee trick is to place the 1/2 cup of Black Walnut 'meat' in a pot of warm water and the lighter 'meat' will rise to the surface while the heavier shell-slivers will sink. Works!
True, the shell-slivers were accompanied by the huge pieces of 'meat'. However, that was fine since we are looking at 2-3 really-really large kernels. Using a strainer I can easily remove all the light 'meat'(kernels).
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<span>Dave</span>Mon, 02/03/2020 - 06:46
I have used hammers to break shells of black walnuts and often hit too hard damaging the fruit. Now I use a bench vice with a one foot extension on the handle and crack the shells in two or three times. It works for me. Also if you like squirrels, walnut trees are a must.
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<span>Jennifer W.</span>Sat, 02/01/2020 - 13:50
On a trip to Ohio my friend's mom had a black walnut tree in her front yard. My mother being a baker with a boyfriend who loved black walnuts, I decided to bring some back home for her. I picked the ones on the ground took them in the house and proceeded to open them and clean them without gloves. Needless to say they stained my hands black. When I came home it was a great story to tell and I had proof to show it had happened! At least for the next 2 weeks...
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<span>Teresa</span>Fri, 01/31/2020 - 16:02
Most Successful first time harvest. looking forward to next years crop. I harvest about 200 black walnuts. I let the outer husk get yucky mushy and black in the wheel barrel , then pretty much washed the heck out of the with the hose. so the floaters got cast out. I Let the nut dry out. I bought a iron Black walnut cracker, which works really well. out of the 200 nuts yield , I was able to get 4 cups of walnuts. nice size. the nuts have a distinct taste. almost to over powering for my thanksgiving stuffing. so a little goes a long way as far as taste is concern. I love em'
Thanks for the tips in comments happy harvesting!
This might seem sad to some. My husband loves. Black walnut trees. We use our fireplace till it get very cold. My husband planted about 40 years ago he says 7500 trees on his property. And he never lets it seed. He cuts the tree after 6 years around 2 foot off the ground. He spaced the nuts 2 feet apart. And 5 acrossed. And left a 6 feet space then 5 more. For a wind break in Wisconsin cold weather. He said it took him about 2 months to plant. And he circled his 24 acres in 14 years. I often tell him so that's why your knees are so bad. By the time I came along he,could even get down on one knee. We have raised beds. For veggies because. The toxins.
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<span>Ken</span>Fri, 01/31/2020 - 14:37
I've owned my property in Tennessee for over 30 years and have unsuccessfully tried to grow BW trees as I like the nuts in fudge and chocolate chip cookies. Last summer I found two seedlings alive and well behind my carport. Must have been buried by squirrels and forgotten. Hopefully they will produce before I leave this earth.
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