Black Walnut Trees

Facts and Features of the Infamous Black Walnut Tree

By George and Becky Lohmiller
January 23, 2020
black-walnut-trees-roots-evil-ascending-the-giants-wikimedia-commons
Photo by Ascending the Giants: Wikimedia Commons

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 all about harvesting and eating walnuts, too.

A Few Black Walnut Tree Facts

  • The easily worked, close-grained wood of the black walnut has long been prized by furniture- and cabinetmakers for its attractive color and exceptional durability. Its 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. 

  • The early settlers discovered black walnuts growing in mixed forests from Canada to northern Florida and west to the Great Plains. They found that its rich-brown heartwood was exceptionally resistant to decay and put it to use as 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, two- to three-inch nuts.

  • Settlers snacked on the nutritious walnuts out of hand, added them to soups and stews, and ground them into meal for baking; the hard shells provided a perfect package for storing the nuts over winter.

Black walnut tree

The “Dark Side” of Black Walnuts

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 in its roots, leaves and fruit husks.

This chemical inhibits many plants’ growth under and around the tree, thereby limiting the tree’s competition, 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 in close proximity to black walnut roots.

A Great Shade Tree

In spite of this, black walnuts make great shade trees for larger properties. They commonly grow to 50 feet or taller and about as wide, and 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 not affected by juglone. In autumn, the leaves turn bright yellow, contrasting nicely with the tree’s rugged, dark bark.

Black walnuts require a deep, fertile soil with a near-neutral or slightly acidic pH. They are pretty much disease-free and are threatened by few pests, with the exception of perhaps an occasional helicopter.

Picking Up the Nuts

Thud! Thud! Most walnut tree owners have a love/hate relationship because of the fruit which the tree drops in late summer though October. The size of a baseball and colored lime green, the fruit is quite heavy. It makes quite a mess and can be viewed as a nuisance.

Walnut tree owners will spend hours picking up the fruit 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 nuts *but be careful not to overpay per nut or you’ll go broke)! 

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Photo Credit: John A. Anderson

Harvesting and Eating Black Walnuts

If you’re willing to do the work of cracking 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 than the English Walnuts more commonly sold in stores and shown at right above.) 

The sweet, earthy nutmeat inside is well worth the effort. Your grandparents may have harvested the walnuts which can be eaten raw or added to baking (cookies and bars). They can also be toppings on ice cream and cakes, enjoyed as a sweetened candy nut, or ground into meal for a unique flour. 

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 simply 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 or drying rack or in a hanging mesh bag. You can store them unshelled 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!

Source: 

This article was originally published in March, 2008 and has been updated.

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Reader Comments

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A Mosstery

The Editors's picture

Hi, Jamie: This really calls for a local arborist, as we don’t know where you are, and even if we did, you don’t say whether “growing all over it” really means what it says, i.e., bark, leaves, everything. And we assume that this is not just lichen growing on the bark. Black walnuts are susceptible to a whole range of pests and diseases, including thousand cankers disease, so it is best to get a professional diagnosis ASAP so that you can begin treatment likewise. Thanks for asking, and good luck!

walnut tree bumper crop

Here in SW Michigan. Our tree has never produced so many walnuts as this season. A friend told us of a conversation he had years ago with an old farmer. He said a heavy drop of walnuts meant a hard, bad winter.
Anybody heard this? Trying to decide how much time to spent in Florida!

This Must Be Nuts

The Editors's picture

Hi, Scott: Thanks for relaying this info. Yes, there is a lot of folklore surrounding what are called “mast” years, when there seems to be an overabundance of nuts and fruit, as though the vegetable world could sense that the animal world was going to need more food during the upcoming winter. Our forecast for your neck of the woods calls for a winter that is not quite so cold as normal but with plenty of precipitation, much of it not in the form of heavy snow. Thanks again!

Black walnut trees DID NOT produce this year!

No walnuts this year after living here for 13 years. Actually it's great that the patio is a lot cleaner, But do they have cyclical growth? Thanks.

no nuts this year

I live in Central Michigan. Last year was a heavy production. This year hardly a nut was to be found. If what you heard is true, I'm hoping my tree is the predictor.

Black walnut trees

I love our trees, unfortunately they have contracted the Thousand Cancre Disease , which my arborist says there is no cure for, and that we will lose them all , I have at lest nine in my yard. I live in Colorado.

I hate my tree

My black walnut tree was there when I moved into my house. I'd cut it down but it's too expensive. If anyone wants the wood pm me and you can have for free if you cut it down!

Hate ours too

Hate ours too

Love the wood

Where are you located?

Black walnut

I’m located in Lexington ky 40509 and will travel any distance I have a trucking company so distance isn’t a problem

Black walnut trees

I have a few black walnut trees if your interested. Trunk circumference is 3-4 ft.

Have two walnut trees for removal

I have two walnut trees I would like removed (for free -- wood is payment). One is about 3 feet & other 5 feet in circumference. (Have a bumper crop of walnuts this year and I'm tired of it.) If interested, I'm in Maryville TN, 37801. Thanks for your consideration.

Black Walnut Trees

We are in Indiana and have four beautiful trees that we would like to have cut and keep some of the wood to make a mantel for our fireplace. Smallest is 40 inches in circumference the largest is right at 70 inches (has two trunks though, the split is 26 inches up). We were hoping to get a little bit of money for the wood, however if we could get them cut and keep two five foot long trunks, we would be very happy with that. Are you interested?

Want to buy your black walnut tree

Someone in the last discussion said they hated there tree and there’d give it away if I’d come get it

I have a big walnut tree in

I have a big walnut tree in my front yard live in Cincinnati send me your contact information If you’re interested it’s more of a hassle than anything!

Anyone hate these trees out west?

Yall are all out east, if I lived within 500 miles of any of those offers I would be all over it (but honestly though, black walnut wood is really valuable, don't give it away for free, that sells for anywhere between $11 and $18 a board foot)

black walnut tree

You serious?

I have a big walnut tree in

April, Is this tree still at your place, how close is it to your house?

Leaves

My 3 black walnut trees only 1-1/2 years old are getting black edges on the leaves also have a English walnut no problems

Large Black Walnut tree dropping large to huge branches

In the past two weeks, we have had 3 branches break off and fall off the 40 foot black walnut tree in the back of our yard. The branches were full of green leaves and walnuts. In fact, as I was collecting nuts for a friend, and clearing them from the back yard so hubby could cut the grass, a branch broke and fell on top of me! Thankfully it wasn't as big as some of the others that have come down, but now I am very cautious about going under the darn tree. We have lived here 20 years and I have never seen this happen. The branches seem to be splitting. I cannot find much help on the internet, and saw that this site was at least current. Hubby thinks this is because the nuts are plentiful and too heavy for the branches. I am not so sure. Any advice would be greatly appreciated.

Walnut Branches Breaking

The Editors's picture

If the amount of walnuts is truly significant—especially closer to the tips of the branches—the weight could cause smaller branches to snap off the tree. However, we would wager that you are probably looking at a pest or disease issue. There are a number of diseases, such as thousand cankers disease, which can weaken the tree and result in broken branches. We would suggest contacting your local Cooperative Extension Service and inquiring about what diseases are known to be present in your area. Pictures of the tree and the broken branches will help them ID the issue, too.

Don't plant near your home or driveway

I have a huge black walnut tree on a small city lot. It is beautiful and provides shade to me and three of my neighbors; all of whom complain about the tree everytime we talk. I refuse to cut the tree down because it is well over 100 years old and it is beautiful; but, it makes a mess of my cars, driveway, yard and roof. My roof and driveway are covered with black stains from where the walnuts fall and break open. The tree drops little droplets of a sap like substance that doesn't easily wash off. I have not been successful growing anything beneath this tree, with the exception of tulips. Seriously... Wait until you get hit in the head by a falling walnut, it's no joke, they come down hard and fast! But, like I said, it's beautiful and old and healthy and I can't bring myself to cut it down.

If you're going to plant one, I recommend keeping it away from your house, decks, driveways, etc. Or, if you don't like your neighbors, plant it near the property line and 20-30 years later you'll have a blast hearing them complain about it all the time!

Black walnut tree nuisance

Don't plan these tree unless you want problems! My neighbor has one on our property line next to our garage in a small city yard. The nuts sound bombs when they fall. The squirrels open up the nuts and leave the shells all over and they stain our driveway, deck and furniture. I am afraid of being hit in the head by these nuts which are extremely hard like a golf ball but are large like like a kiwi. It's dangerous to be near this tree. Also, once thel broken shells dry, they are sharp so forget about walking barefoot in your own yard. Now a raccoon has build a nest in the neighbor's nightmare tree. Not to mention the damage the roots did to my concrete sidewalk and garage floor. I could go on and on but do yourself and neighbor s a favor, don't plant a black walnut tree and be diligent about getting rid of all weed trees on property lines. Trust me you are not going eat these nuts.

I have NEVER seen a raccoon

I have NEVER seen a raccoon build a nest in any tree

Black walnut trees

We had a beautiful black walnut tree in our back yard, but Dad had it cut down because it was killing everything else he wanted to grow back there. But the wood did make a gorgeous cedar chest. The finished wood looked like gray to black velvet. The gray just faded into small areas of dark and back again. Oh was it gorgeous.

Black Walnut Tree

After we have cut down our black walnut trees we want to plant maple trees near their stumps.

Is this a good idea.

replacing a black walnut tree.

what trees can we plant where our black walnut tree was?

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Maples

You can plant red maples by walnut trees. Some of the trees you can’t are, saucer magnolias, pines, apples, crab apples. I’ve had trouble with ginkgos, lilacs, pines and apples.

trees

We have Black Walnut trees. They are beautiful. We take the nuts and replant to make new.

Walnut keep on giving

As a novice woodworker, the black walnut wood is beautiful. I am always looking for walnut trees that have served their useful life and now can be put to further beautiful use. Connect with me if you need to get rid of one near Dayton OH.

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