Cynthia is a digital marketer, writer, and artist. She writes about a variety of topics, especially digital marketing, languages & culture.
Black Walnut Trees Are Toxic to Some Plants
When I first moved into my house, there was a really large tree in the yard, and I was curious to know what it was. I quickly found out by identifying the large nuts that fell from it only a couple of months later: a black walnut tree.
When I mentioned this to my sister-in-law, she said that the tree would grow even larger and to be careful about what I planted near it. I heard her words, but soon forgot.
Over the next year, I planted lots of plants in my yard: tulips, wildflowers, phlox, and more. Nothing was growing. I had resigned myself to a brown thumb. I sat on the porch, staring at the tree when I suddenly remembered what my sister-in-law said.
Immediately, I thought about cutting down the tree. So much of what I had tried to plant in my yard died within days or weeks of planting. I’m glad I didn’t cut it down, though. I began to do more research and decided not to fight the tree, but to work with it. Besides, I have a really hard time justifying cutting down any tree. They provide oxygen, shade, and in this case, nuts.
Over the next few years, I would grow to love this tree. I really began to learn so much about it and now I feel like it has taught me a few things, too.
About Black Walnut: Appearance, Growing Habit, Fruit
Also known as Juglans nigra, this tree grows in eastern North America in Zones 4–9. It likes fertile soil, and even likes the soil to be slightly acidic—at least in my experience. The pH of my soil is around 5.5–6 and a lot of black walnuts grow all over near where I live.
If you want to cultivate your own black walnut, you can do so by planting seedlings or grafts. It doesn’t like areas that tend to frost before others, such as near bridges or in low valleys. Black walnut trees need full sun and can grow up to 100 feet tall, with a spread of about 70 feet. Their leaves grow side-by-side in a pinnate manner.
Around September (or late summer/early fall), the tree starts dropping its green fruits that contain a hard-to-crack nut. The green fruits ripen to a brown color.
These trees emit a chemical called juglone, which is responsible for inhibiting the growth of many plants. However, I have found that a number of plants do survive and even thrive around black walnuts.
It seems like a number of acid-loving plants don’t mind black walnut. In my own yard, violets and plantains happily live right under my black walnut tree, as well as my hosta plants. Azaleas, native daylilies, and astilbe are all perfectly happy, as well. My crocus plants and daffodils don’t seem to mind it, either. A search of black walnut toxicity will display a list of what can and can’t grow near the black walnut.
Uses of Black Walnut
The nuts, hulls, bark, and wood are all parts of the tree that humans can use. They have many health benefits and healing properties. Black walnut wood is a highly prized hardwood. This hardwood can fetch handsome prices because it is durable and when stained, it has a beautiful texture and color.
Read More From Dengarden
The bark, if scratched off a bit, is a great laxative tonic that is said to be safe to use during pregnancy (but it’s always good to check with a doctor or certified herbalist to be sure, and for correct dosage requirements).
Herbalists will use the hulls to make tinctures and dried powders. These then become remedies for athlete’s foot, and a few other fungal maladies that afflict people. The dried powder is a main ingredient in salves and foot powders that herbalists make to also treat fungal infections. The hulls also help with skin diseases, especially ones considered to be “wasting” diseases. It is good for cold sores and even eczema.
The hulls can also be used in internal applications. Some herbalists will put them into capsules for exact dosages. Others might make tinctures to aid with gastrointestinal problems, such as constipation or even diarrhea. The tincture also helps to detoxify the blood.
The nuts inside the hulls are incredibly delicious. They have a slightly unusual flavor for a nut—it tastes really earthy, almost has a cherry-like aftertaste. They are a rich source of fatty acids. Some herbalists and doctors will recommend eating plenty of black walnuts for patients with a history of eczema.
The nuts also have a high oil content and these are great at helping people to rebuild cellular strength and improve heart health. They are loaded with those wonderful Omega-3 fatty acids.
Processing Black Walnuts
This is an interesting task. The first thing you need to remember if you’re going to be working with black walnuts is that they will stain anything they touch. In other words, when you’re processing these, be sure to wear old clothes, shoes, and gloves.
The tree in my yard drops about 10–15 nuts per day during the month of September. I’ll process them every 1–2 days so that I don’t spend a lot of time processing hundreds of nuts at once—I do have a life. I also know that if I wait, the hulls will get extremely ripe and not be as good to work with.
The first thing you need to do is collect the fruits. Wear gloves even while doing this because some of the hulls crack when they hit the ground, letting the black juices flow to the outside.
Don’t try to shake the fruits from the tree. Usually, the fruits are extremely high, and the branches can break, either by you standing on them or by shaking them. The fruits do not come off easily, either, until they are ripe. Then, they fall off by themselves. So, just do your collecting from the ground. You might even live to see another day.
Next, you need to de-hull the fruits. Some people talk about running over them with their cars. I have never tried that, nor do I care to. I can tell I would be peeling squished hulls off the tires and really, if I’m eventually going to be eating these, that really doesn’t sound appetizing.
The fully-green fruits will be a little harder to de-hull, and the brown ripe ones will already be mushy and easy to get the hull off.
Don't Get Stained!
What I do is wear heavy boots. I place the fruits on a rocky/gravelly surface. The rocks help to break up the hulls and give me a hard surface to work against. With the ball of my foot, I apply some force to the fruit to squish it. The green hulls don’t usually take too much effort and the brown fruits I just de-hull with my hands.
I place the green hulls on a drying rack so that I can use them to make my own tinctures and powders later on. I place the ripe hulls into a plastic bag so that I can make dye and ink with them. They need to sit for about two weeks. I will admit it’s a moldy, slimy mess, but I promise, the end result is worth it.
As you work, you will encounter juicy walnut fruits from the really ripe blackened hulls. If you use your bare hands, you risk staining them for weeks. I used leather gloves and even those aren’t ideal because the juice can get through. I have stained fingers as a result, and I rinsed my hands and gloves often!
You might see some maggot-like creatures on the hulls, called Husk Fly Larvae. You can especially see them on the very ripe ones as you’re de-hulling. While they are gross to look at, they don’t hurt the nut at all. They just like eating the hull for food. I admit, though, it still grosses me out a bit to be squishing those things off with the hulls.
Avoid using the hulls with maggots if you’re going to be making tinctures and powders. Just throw those hulls in the black plastic bag. It’ll fry the little maggots and well…it’ll add a little protein to the dye you’re going to make.
Rinsing, Drying and Storing the Walnuts
Once you have de-hulled the nuts, the next step is rinsing them off.
I will get a large bucket and put all the nuts on the bottom. I completely cover the nuts with water, and discard any that float to the surface. I have heard that these nuts aren’t as good and/or are getting rotten, so I do not use those.
Next, you’ll want to dump the water out, preferably somewhere where you don’t care where the water might stain something. Thus, if you dump it out on a sidewalk, it will turn brown for a while. The water gets black when you’re rinsing the nuts!
I’ll fill the bucket and rinse the nuts at least one more time. Then, I dump them out with the water.
If you have a wire basket handy, this is a great use for it. Just dump the water and nuts into it.
Place the nuts in a cool, dry place to dry and cure completely. You do not want to eat the nuts, yet. They need to cure for about two months before you ever taste one.
Storing Your Nuts After Curing
After hulling, it’s extremely important to put the nuts where they will be cool and dry, with good air circulation. If not, they will get moldy and won't be any good.
While the nuts cure, the shell actually retracts from the nut itself, so that when you go to crack the shell, the nuts will actually pop out much easier. They still like to hang on to their little compartments, though. Even after breaking open a shell, it’s often maddeningly difficult to get at all of the nutmeats.
It’s a good idea, if you don’t plan on eating the nuts right of way, to freeze them. They will stay fresher, longer - for up to two years. Otherwise, refrigerate them up for up to a year.
Cracking the Nuts
If you have ever done this by hand, you will know that this is no easy task. The shells on the nuts are so hard, that it takes a lot of muscle power to get at the nuts.
Hammering them open is an option, but you risk damaging the nut inside, too. If you use a small hammer, though, it's actually not that bad.
You can use a nutcracker, but you might break it if it’s not specially designed for walnuts.
I have resorted to a vise-grip before. They usually do the job just fine, without squishing the nut inside. Actually, my husband usually does the vise-grip-nut-cracking. I just enjoy the nuts.
It’s a labor-intenstive, muscle-building process, so we usually just eat a few at a time. At some point, I’ll crack enough of these to put in cakes and breads, but for now, I just enjoy them with a little salt.
About the Dye and Tinctures
I won’t go into the dye and tinctures in this article. Actually, here’s a little secret: I haven’t made the dye/ink before, nor have I made tinctures. But, I’m might try that this year for the first time.
I got this crazy idea in my head, you see. Since the stain lasts for weeks on your skin, I thought about making “skin ink” from the walnut hulls.
I might also be inspired to make “earth paintings” with the ink I’ll be making. Right now, those hulls are fermenting and molding nicely for my dyeing adventure. Wish me luck!
- Gladstar, Rosemary. Herbal Recipes for Vibrant Health. Storey Publishing: MA. 2008.
- Wardwell, Joyce. The Herbal Home Remedy Book. Storey Publishing: MA. 1998.
- Brickell, Christopher and Judith D. Zuk. The American Horticultural Society A-Z Encyclopedia of Garden Plants. DK Publishing, Inc.: NY. 1996.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
© 2012 Cynthia Calhoun
Susan on July 03, 2020:
Hi. Just found out we have a black walnut tree in my yard. Only this year I noticed nuts on the tree. Had to leaf snap it to find out what tree it was. Enjoyed your blog with full of great info. Maybe I will get ambitious bout harvesting this September. Thanks
Morty on October 06, 2019:
So that’s what you can do with all those round bombs hiding in the leaves waiting to trip you up.... so please, come and get all of mine. We get hundreds every year from one tree ... my neighbor and myself keeps telling each who really owns the tree and the round devils. I use a pooper scooper to gather them without destroying my old back.
Enjoyed your humorous writing though.
kathy schedler on September 09, 2019:
thank you for your inspiration. I'd heard you could eat the nut but had no idea how to process. I really only knew of the wood being valuable to furniture makers. looking forward to making the dye and using it and tasting my first black walnut.
Cyndi80-98 on July 18, 2019:
Wow! This article has given me so many great ideas for the black walnut tree in my backyard! I didn't even know what these things were until today lol. We had a heavy storm yesterday and I found a few that had fallen on the ground due to strong winds. Thanks for the info, Cynthia! I'm looking forward to hearing about the dye...I was thinking it would make a great temporary hair dye, I have dark brown hair so this would make a great match for me.
RHONDA Minnis on July 22, 2018:
I was just talking to a friend about black walnut how is fighting intestines parasites
Jim Stark on October 21, 2017:
I found that a pair of bricks (not massive ones but regular old bricks) works very weak for cracking these nuts. I put a few on the back, back lightly, and they're open but not shattered. I have thousands of these fall at my law office and we have them picked up so they don't kill the other plants. Shame to waste, so we power wash them in a large wire basket (peels them and cleans them immaculately at once), then dry out on a bed of newspapers (or old paper we don't need), and a few months later, exceptional nuts. The bricks to crack are optimal as the nut breaks with little pressure but doesn't destroy the "meat."
gerri detloff on October 09, 2017:
we have a huge black walnut tree in our yard it is very old. A friend after realizing i had this in my yard said i should bag them in one pound packages and sell them. Evidently there are people looking on the buy sell and trade to purchase them. Im considering
Cynthia Calhoun (author) from Western NC on October 08, 2017:
CJ - I'm not giggling at your predicament, but I am giggling at how much you hate black walnuts. Hehe. I'm sorry you've had this experience with it. I have five or six in my yard and where we live, the people had to build a carport to keep the nuts from bouncing all over the cars in the driveway and the nuts falling WILL dent up your car. Yes, the nuts are crazy and loud when they fall, they stain, other plants can't grow near them, and it's crazy. I suppose it's one of those things: I suppose that if there is no finding appreciation in the tree, you have several options: perhaps build a carport, keep the branches trimmed, convince your neighbor to cut it down and sell the wood (though I love trees and try to avoid cutting them down) or...elicit neighborhood kids to collect the nuts and crack them and you can sell them for $9-$10 a pound. :) Good luck and watch out above.
Cynthia Calhoun (author) from Western NC on December 26, 2012:
GoldenThreadPress - that's wonderful! I love them, too, though it's SO HARD to break the outer shells, haha. Thank you for your feedback. :)
GoldenThreadPress on December 25, 2012:
I grew up with seven black walnut trees, suffered through a worm infestation and had to pick up thousands for my family. Do I love them still? I do! I have some in a wooded area behind my house. When the squirrels drop them into my lawn, I collect them and remember my childhood-- :) --Deb
Cynthia Calhoun (author) from Western NC on November 07, 2012:
Sharon - that's so cool about your friend. Did you all end up going through with it? Is she making walnut pies? Hehe. Thank you so much for your comments.
Newusedcarssacram - thank you so much. I appreciate it.
Kelley - they really are great for you. A bit of a pain to crack, but fun. :) Thank you, my friend.
RTalloni - yeah, the strong flavor can take a little getting used to. But I love, love, love it. :)
Natashalh - that sounds like so much fun! They have a distinct taste and smell for sure. Ah...family traditions are so fun.
Natasha from Hawaii on November 07, 2012:
As a kid, I would gather and shell walnuts with my grandfather. Their distinct smell - both the trees and the shells - is probably what I remember more than anything else.
RTalloni on November 07, 2012:
What a great resource this hub is for black walnut info--thanks! I love the strong flavor of this nut, but not everyone does. I love your idea of creating art with the ink and I hope we get to see some of your work.
kelleyward on November 07, 2012:
Wow no wonder they are so good for you. You did a fabulous job with this article. Sharing it and voting it up now!
newusedcarssacram from Sacramento, CA, U.S.A on November 07, 2012:
Awesome...I loved this hub and its interesting content. UP!
Sharon Smith from Northeast Ohio USA on November 06, 2012:
Wow, I never saw this. Awesome article with SO much detail. It really intrigued me because a few years back, I was talking with a friend of mine about planting black walnut trees on her property (for the nuts to be sold). We did all kinds of research and I'll tell ya, your article here is a great resource. Bookmarking!
Cynthia Calhoun (author) from Western NC on September 29, 2012:
Unknown Spy - thanks for coming by to another hub! :) I love walnuts, too. They are mmm, mmm good! Cheers!
Life Under Construction from Neverland on September 28, 2012:
Whew!!! great photos and very interesting article! i love walnuts :)
Cynthia Calhoun (author) from Western NC on September 28, 2012:
The Dirt Farmer - I agree on all fronts! I just processed more of them this morning and now my fingers are REALLY brown. Hahaha. Oh well, it's SO worth it. :D Thank you for coming by!
MM - those larvae ARE GROSS! Hehe, I was just thinking that I'll have to get a picture of my making a really grossed out face when I make the hulls into dye. Those bags are fermenting and moldy and...gross! HAHA. Thank you for stopping by! Hubhugs!
Movie Master from United Kingdom on September 28, 2012:
Hi cindy, yep those larvae look gross....
I have never heard of or seen black walnuts before and found your article fascinating.
Great to see a photo of you too!
Wonderful hub thank you and voted up.
Jill Spencer from United States on September 27, 2012:
Love black walnuts! We used to run over them with a truck to get the hulls off. Picking out the meat's a tedious task, but the walnuts you get are well worth it. Enjoyed your hub!
Cynthia Calhoun (author) from Western NC on September 27, 2012:
Sally's Trove - you know, it was a bit of an acquired taste with the walnuts for sure. LOL. But now, I love them. The trees and nuts are so fun. It's crazy to hear them come crashing to the ground. I'm always a little scared one will bonk me on the head when I'm collecting them. Oh yes, the "dye" adventure is sure to be an interesting one. :D
Sherri from Southeastern Pennsylvania on September 27, 2012:
What a wonderfully rich hub. It is now my "virtual" black walnut adventure, as I don't have any black walnut trees near my home, although I used to until we moved.
I never cared much for the taste of black walnuts, but I found the tree and its fruits interesting to watch. I admit that we ran over the nuts with our car, but that's because the trees dropped them right there on the driveway!
The pictures are a real treat. Can't wait to hear about your dye adventure. Up, awesome, and all that. :)
Cynthia Calhoun (author) from Western NC on September 27, 2012:
Alocsin - I know you're on the west coast, so this tree doesn't grow out there, but I bet other varieties of walnuts do. :) They are really good for you. Thanks for stopping by!
Mecheshier - Aww, I love those kinds of memories - the ones where a scent, a taste or the act of doing something reminds you of home. :) The whole process of dealing with the walnuts is one where I could see how it would create such awesome memories. I hope to continue my own ritual of "walnut processing" from year to year. :)
mecheshier on September 26, 2012:
Black walnuts remind me of when I was a child. They were everywhere. When I moved away from home I missed them very much and the figs!. At Christmastime my mother would ask me what I wanted , I always answered Walnuts. She always sent me a gift and used walnuts for packing. :-)
Aurelio Locsin from Orange County, CA on September 26, 2012:
What a comprehensive view of a plant I knew nothing about. However, it sounds like a nut worth pursuing because of its health benefits. Voting this Up and Interesting.
Cynthia Calhoun (author) from Western NC on September 26, 2012:
Teaches - aww, you had black walnuts, too?! That's awesome! I love the tree we have growing. At first I didn't like it, but then when I figured out all the cool things about it, I had no idea that it was so useful and awesome! Thank you so much for stopping by. Many hubhugs to you!
Dianna Mendez on September 26, 2012:
This brought back memories of when I was a child. We had a huge black walnut tree in the backyard. I remember them falling from the tree and how they stained our hands when we picked them up before mowing. Great post and very well done. Voted up.
Cynthia Calhoun (author) from Western NC on September 26, 2012:
Mecheshier - thank you! I have definitely grown to love this tree and I'm very curious to see how big it will grow. Yes, roasting them sounds SO GOOD. I can't wait to try that. :)
Aviannovice - yeah, so many things will still grow around black walnut. They get a bad rap, though, because things like strawberries and tomatoes won't have anything to do with this tree. LOL. Corn, beans, and squash don't mind it, though. That's awesome.
Terrye - haha, you make me grin! Yes, it's a continuing saga...and my fingers are getting browner, and browner. Haha.
Terrye Toombs from Somewhere between Heaven and Hell without a road map. on September 26, 2012:
Yay, you finally finished this hub! I couldn't wait to read it! Nicely done! Now, I eagerly await the next saga in the black walnut saga! :)
Deb Hirt from Stillwater, OK on September 26, 2012:
What a wonderful tree that gives so much. Sounds like you can still plant plenty of things around it, though, so its juglone doesn't matter that much. You could just find other homes for the other flowers that you'd like to plant.
mecheshier on September 26, 2012:
Fabulous Hub. It is very informative and well written. Walnuts are a favorite of mine.Love the pics and suggestions. Like cclitgirl, I will definitely have to try roasting them with cinnamon and butter. Sounds great. Voted up for awesome.
Cynthia Calhoun (author) from Western NC on September 26, 2012:
Tammy - MMM! Roasted black walnuts with butter and cinnamon. OMG, I'm going to try that. We have like 5 coffee CANS -ful of nuts to eat. LOL. They are so good anyway - that just sounds heavenly! Thank you so much!
Faith Reaper - Thank you for stopping by! I do love my black walnut tree. It's not too bad processing the walnuts. My husband thought it would be funny to take a candid shot of me doing that. Haha. Thank you for the votes and shares. :)
Faith Reaper from southern USA on September 25, 2012:
What a very extensive hub on black walnuts and their health properties. Very insightful and interesting. Love this. You look so happy while processing the walnuts. Cute photo. Thanks for sharing all of this valuable information here. Voted Way Up In His Love, Faith Reaper
Tammy from North Carolina on September 25, 2012:
Fabulous hub! I didn't realize these nuts had so many great health properties. My brother and I used to pick them and crack them. There isn't a better snack than having these toasted in the oven with some real butter and cinnamon on them. I love them in breads too. MMM... Sharing!
Cynthia Calhoun (author) from Western NC on September 25, 2012:
Carol - wow!! You came by so quickly after I published! Extra-special HUBHUGS to you! I love nature's remedies and the beautiful things she can provide. :) Thank you for the votes.
carol stanley from Arizona on September 25, 2012:
I am amazed and I am always amazed at the pharmacy we have out in the growing fields. I loved the photos and all the information that I had not a clue about. Thanks for sharing this great hub. Voted UP.