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)! 

black-walnut-shutterstock_182861756_full_width.jpg
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.

Reader Comments

Leave a Comment

Had No Idea that I had Black Walnut Tree in my backyard!

My kids and I have noticed this big, shady tree in our backyard for quite some time but never researched it until this year. We noticed many clusters of fruit hanging from the tree, and waited for them to fall to the ground. We were curious, so we cut open one of the fruits when they fell to the ground. To our surprise, the inside looked like an avocado but when we googled it- we found it to be a black walnut- Wow, you never really know what fruits can grow on trees, in your backyard!

Grew Up With Black Walnuts...

...in our backyard in NW Iowa. Several trees. So many memories attached to them I haven't thought about in 2 decades. The big strong shady trees themselves. The spotty vegetation underneath. All stages of the fruit dropping, rotting, staining everything everything (hands, sidewalks, streets). Squirrels, lots of squirrels. The thin spines of the leaves that shed. The walnuts all over the street & cars popping them as they drove over. Dodging them on my bike. For some reason, we never harvested & ate them, I wish now we had.

And the smell. I'd forgotten about the smell till this article. That pungeant smell of the tree & leaves, and of course the fruit too. So many fond memories attached to those crazy trees.

Black Walnut Tree

I have approximately 20 Black Walnut Trees on my property and the largest is approximately 150 years old

Black walnut

I have about 6 plus trees in my yard. I love the nut to eat and to bake with. If you want one to grow. Just simply get a few from someone you know and put them in the ground and come summer you'll have one. The squirrels love them.

Blooming

Its mid may and my 3 black walnut trees havent started getting leaves yet. Is that normal

I can’t stop crying

Maybe the isolation is getting to me, but the people kitty-corner to me just had their black walnut cut down and ground up, and I can’t stop crying. I’ve lived here over fifty years: I knew the people (long since deceased) who planted that tree. The tree itself was beautiful and ostensibly healthy; it provided shade and shelter. Now it’s gone. The only reason I couldn’t see for removing it would be so that the new family in the house would have a clearer path for their massive, far-too-big-for-the-job riding lawnmower. Like I said, maybe it’s the isolation, but aren’t enough things dying right now? We have to impulse-kill trees, too?

Green walnut juice

For ringworm, rub the affected area with the juice of a "green" black walnut. It will kill the ringworm.

Black walnut tree

I have always heard that a black walnut tree will not bud out until after the last frost. And I have seen it happen every year with mine.

Picture of Nuts Not Correct

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.

Duly Noted

The Editors's picture

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!

Dogs

Are the fruit harmfull to dogs we have a tree in big bear CA

Dogged Problem

The Editors's picture

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!

Sorting Meats from Shells(old Cherokee method)

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).

cracking black walnuts

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.

Wish I had read this year's ago.

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...

first timer harvest

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!

Black walnut

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.

Black walnuts

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.

Hulling Black Walnuts

I grew up in the Southeast Missouri Ozark's where there were many natural black walnut trees in the woods. My dad would send my two brothers and I out to find and bring back the black walnuts in flour sacks. We would do this three times every day, for a week, and dump them into the trailer attached to the Jeep.
Dad had made a wooden tray that had 6” high sides, it was a little wider than the rear Jeep tire and about 3’ long. He would jack up one side of the Jeep and slide the tray under the tire until about 2/3 was under the Jeep and about 6” out the back. He would then let the Jeep back down until it was about 4” off the tray. He would drive a steak into the ground to keep the tray from moving from under the Jeep. He would put a big rock in front of the rear tire on the ground, then start the Jeep. He would put it in third gear and let the clutch out slowly. The raised tire would start turning and we would start throwing the harvested walnuts under the tire in the tray. The hulled walnuts would fly out the backside of the tray. We would place the hulled walnuts on a large screen shelf. When we filled up the shelf, we would stop hulling and let them dry out for 5-7 days. Then we would start the process all over again until we hulled all of the walnuts we had harvested that one week. We had two outside dogs, so they kept the squirrels off of the hulled walnuts on the screen and we covered the walnuts in the trailer. We did not have much money so my dad would barter the hulled black walnuts for things my mom or he needed.
I did this every year from the time I was 7 until I went into the Marines, then the harvesting fell upon my younger brothers.

Black Walnut Trees

I have lost 7 huge black walnut trees in northern Colorado to a disease called 1000 canker. They were mature trees planted by my great grandfather. We cherished the nuts and used them as anticipated Christmas gifts. We would gather the nuts and put them in the driveway and run over them to remove the hulls, then pick them up (wearing gloves) before the squirrels got to them. We would then wait until after the first freeze to crack them using a nut cracker from England, spread them out on the kitchen table and separate the nuts from the shell. The trees will be missed for their shade, nuts, fly repellent and beauty. Sadly, it is rumored the this disease will remove black walnuts from our planet.

Black Walnut trees

We harvested our Black Walnuts for the first time about 4 years ago.We have 4 trees in our yard thus quite a few walnuts yearly. My husband saw a video on a way to get the hulls off easily with a pressure washer so he tried it. BIG MISTAKE! He did not cover himself and the "stain" got all over him. We joked at first, until the stain spots became burns and started eating into his flesh - all over his head & face. He had to go to the Dr. for medication to treat the acid-like burns. His Dr said he had never seen anything like it and took photos to share with his colleagues for future reference. My advice is to take the hulling process very seriously to avoid painful burns from coming in contact with the outer coating of the nut.

Black Walnut Memories

My grandmother had a Black Walnut tree behind her shed. We gathered the nuts when they were brown, hulled the, she cracked them, and us kids helped her 'pick' the nut-meats. She always made a cake during the Holidays using the Black Walnut meats, raisins, and coconut ground through her meat grinder to make the icing for the cake. She called it a Rocky Mountain Cake & it was delicious! I wish I had her recipe.

Black Walnuts

Never use Black Walnut sawdust even in partial amounts(10%) for horse stall bedding will cause Laminitis (Inflammation of the hoof) also called Founder. Horses can show signs of Laminitis in as little as 10-12 hrs when bedded in byproducts of Black Walnut.

black walnut trees

i have 6 they are great , did not know, you cant plant anything within 50 feet or more
i have a garden within 15 feet of one havent had the best of luck smoethings did grow but others didnt , guess its time to considder moving the garden

Black walnut hulls

I use the hulls for a natural antihistamine, destroys infection, dog dewormer, stops toothache pain in 30 minutes for most people as it kills the germs eating the nerves causing the pain. Let alone the fact it stops steel from rusting. Black walnuts are an amazing tree GOD gave us as the nuts are good for our heart health when eaten.
Works to stop acid reflux if caused by sinus drainage, even for smokers.

Barbara - Lumber - cut down tree

I would be interested in removing the tree for you.

walnuts Black

Are the black walnuts still good to harvest underneath the snow

Walnuts

We recently found black walnut trees on our land after clearing brush. It’s the season for them to drop. How can we tell that what is on the ground is this year or a prior year?

lumber

We have a huge, very healthy black walnut tree that we need to cut down. Does anyone buy the logs or any part of the tree?

Walnuts by the Driveway

After reading these comments, I can understand why someone long ago planted two black walnut trees along the driveway! We just moved into our house a few months ago and have been popping over these walnuts for weeks as they've dropped to the ground. I wish I had paid more attention and known they were walnuts before now, as their ripeness has long passed. Everything adds up - squirrels have shown up and have been eating and storing them in our shed, the fruit and the trees themselves have a distinct smell, when I tried to hull one my hands got stained, and the trees are the tallest and strongest trees we have. What a nice surprise that came with our new home. Now to treasure them and get prepared for next year's harvest!

Pages