Black Walnut and What You Can Do With It
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 to not 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 look at 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 many 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.
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.
Would you go to all this trouble to harvest and process black walnuts?
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 awhile. 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.
Have you ever cooked with black walnuts?
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 hub. 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 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