Black Walnut Trees

Facts About the Infamous Black Walnut Tree

By George and Becky Lohmiller
August 19, 2020
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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 how to harvest and eat the tasty walnuts, too!

Facts About the Black Walnut Tree

  • 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. 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, 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 or within the tree’s drip line (i.e., under the tree’s canopy). Plan your landscaping accordingly!

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, 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 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.

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 the dropped walnuts (just be careful not to pay per nut—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 in the photo 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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Black Walnut Trees

We have 4 Black Walnut Trees in our yard. We do love / hate them! The nuts are ankle breakers if not collected. I have a "walnut wizard" which makes picking them up SO easy! I couldn't co-exist without it! The hulls are dangerous. My hubby blasted them all off with a pressure washer one year and the next day he was covered in acid burns. He had to seek medical care and was on allergy meds & burn cream for a week. His Dr. said he had never seen anything like it! BEWARE THE HULLS!!!

Black Walnuts

I grew up on a farm in Virginia with a black walnut tree in the front yard. We would gather the green nuts and pile them under the tree. When the hulls turned black, we would put them in the driveway and my father would run over them with his truck to break the hulls off. Then we would spread them out to dry and crack them open with a hammer on a good hard rock. Yes we went to school with stained hands but so did other kids. We all knew this was stain and not dirt, so no one cared. They also knew it was because we were doing our part to help the family. Those were good memories!

Love My Trees

In a small Northeast Central Indiana town we have a Black Locust, a Black Walnut & an Ash in a row between two houses. Our neighbor is scared to death every time a Walnut drops on his house. They can be dangerous when they drop. I had one break a windshield on our car while driving a couple of years ago. Our Squirrels seriously enjoy them & since I supplement their diets with peanuts & bird seed during the rest of the year, we enjoy having them around as well. Before I just mowed them each year but now that I use a Battery powered SunJoe mower, I rake the nuts 1st (less power than a gas mower). Never a problem with the roots or Juglone. Our property is a Certified Wildlife Habitat through the NWF (National Wildlife Foundation) & the tree provides part of the requirements for certification. Not my favorite tree because of the clean up work but they provide great shade, critter habitat & are otherwise maintenance free. I think I'll keep it!

Black Walnut Trees and Pear Trees

I would have to say that the comment about the Walnut tree roots producing jaglone and it inhibiting other plants from growing is slightly miss leading at best. I have a Pear tree which produces fruit that is partially hollow and it has a Walnut tree growing out of the hollow spot at its base that also produces fruit. The pear tree is the oldest of the two and has been around at least 40-50 years the walnut tree has been there for at least 25-30 of those years.

Black walnut trees

They are toxic to horses! The leaves and the nuts and the grass underneath the tree.

I Would Share My Opinion But I'd Get Censored

Comments on black walnut trees ??? I'd rather be eaten alive by fire ants than to ever buy another house with them anywhere near it. We have a squirrel infestation now and they destroy everything. They chew those shells into a summer long rain of gooey bits just coating the yard and house. It stains everything and looks like green bird dung. The nuts are ankle breakers and I have to hire a kid to come and clean my deck once a week, but i can only use it for a day afterwards before it's covered again. I despise these trees. Worse thing on earth to have within a mile of your dwelling. I'd love to buzz the last plank of the last walnut tree through a planer !!

Black walnuts are a pain!

I have 3 large Black walnuts near where my driveway meets the street (neighbors have others, also near the street). When the nuts drop, the go 'splack!' onto the pavement; then, when cars drive over and flatten them, they become ugly black 'pancakes' that last forever on the street. I used to broom them off to the road side as soon as possible to avoid that, but my disabilities have restricted my neighborly actions. I tried pickling them one year; gathered, and put in baths of brine, covered for a couple of weeks. Result: A lot of mess, wasted water, brining salt, and time. This year, I'll consider picking up a few and following the guidance posted in this article. I do love the shade, however; helps reduce my A/C use.

Black Walnut Tree

I've had a black walnut tree hovering over my backyard for 25 years now. Squirrels have built tribes surrounding it. The only drawback? When those suckers fall? It sounds like gunshots on the patio table. They float in my swimming pool. However, I love it and will continue to nurture it. I'm going to try to harvest some and use them in my cooking.

Thought it was something else

We just had a 60+ ft Black Walnut tree cut down. We didn't want to because it shaded 2/3 of our house and yard in the Texas summers. The rings on the inside of this tree made it at least 100 years old!

Thought it was a chestnut tree

I lived in my house in Toronto Canada for 10 years and thought her backyard tree was a chestnut tree I just found out it is a black walnut tree. The walnuts are still a golf ball size and wondering when they will become the baseball size tree is about 10 years old.

Get rid of black walnut

How hard is it to destroy this tree? I have one, about 10ft tall, growing between 2 houses approx 10 from each other. Obviously the roots will damage both foundations. Help!
(If this tree can be moved, I'm happy to try, but it's a smallish residential lot.)

Black Walnut

I was looking up the black walnut to understand how long the tree survives. I have a very large one towering over my garden and my neighbours garden from 2 doors over in the beaches area of Toronto. Everything I read about it in the almanac rings true. I’m amazed at the 250 year potential age. My neighbour hood is 100 years old and over the last 15 years all the Norway maples have died and only the black walnuts remain thankfully giving shade and a beautiful green coverage. Walnuts can be nigh on lethal but the squirrels tidy them up pretty quickly. Good to know that the tree cover will remain for potentially another 100 years.

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.

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