Juglone Sensitivity List

regarding your particular important question: at one of our orchards, we planted 100 aronias in many of the halfway points between nut trees (pecans-to-be-grafted-to-hickories and walnuts, all still small enough that there is no noticeable effect from those trees on the aronias). the orchard is surrounded by native trees, including walnuts from 4" to about 2.5' in diameter. we've noticed a strong correlation between an aronia's proximity to any of the larger walnuts and the likelihood of the aronia struggling to grow and in some cases dying. i don't know that i've seen enough to be 100% sure of the cause, but i would tentatively put aronia in the juglone-sensitive group.

and per that other thread, blackcaps, pawpaws and persimmons in the juglone-tolerant group

Thanks Greg!  I did a lot of looking online without much info on aronia and juglone.  Unfortunately I risked it and put a bunch of them near a couple baby butternut trees.  I guess the clock is ticking on them  Thanks for the info!

Its definitely NOT a permaculture plant but I can say Russian Knapweed DOES NOT tolerate jungelones.  I have a field being overrun with the stuff.  It kills the grass and the cows wont eat it. I hate it. BUT in same field I have a mature grove of Black Walnuts and not a single RK plant can be seen under them.  Grass grows beautifully thick and lush.  My long term plan to get rid of RK is to plant black and white walnuts, black cherry and black locust as mixed rows  in my fields as silvopasture system.  I find it a bit ironic that while I would never spray roundup or some such in my fields I'll happily use jungalones , another herbicide  albeit a natural one to achieve same end.  I might be a hypocrite but I dont feel bad. lol.

I cant confirm (yet) but have heard that black locust, black cherry and pawpaw are all unaffected by jungalones.

Good deal. I have some black walnut...nuts...in my fridge, doin the stratification. I'm thinking I might need more. What's a ballpark density for black walnut in a stand? One every eight feet? I think I'll plug black wall nuts in the soil in an area where I do black locust seed and bare root persimmons. Thanks for the ideas.

After doing my research, I think that juggalones are misunderstood.

Hi Ben, I think the ideal density depends on what you're after.  If you want veneer logs in 60 years, the spacing is probably larger.  If you're wanting maximum nut production in a polyculture it's something different.  In my butternut guild I put 4 seedlings about 4' apart.  I figure in the forest they grow that close and this way if a few die, I didn't waste a 40' area on a tree.  Since I planted them three years ago, two of the four died so it's working out

I just re-watched this Edible Acres video on designing around Black Walnut.  Per Sean's experience, Autumn Olive, pawpaw, black locust, black raspberries, elderberry and comfrey are very tolerant.  Hazelnut, raspberries, persimmon, redbud and chestnut are somewhat tolerant.  They'll live there but not thrive.  

I have many black walnut trees in and around my yard. To the question about the effective range of their "weed control", in my experience the jugalone effect is mostly in the roots, which extend well beyond the drip line in a mature black walnut tree.

Plants I've seen tolerate black walnut include chives and garlic, blackcaps (wild black raspberry), raspberry, sour cherry trees (Montmorency), peony, and strawberry.

Plants that I'm certain can't tolerate black walnut include rhubarb and tomato. There's plenty of others with mixed results I'm not sure enough to list.

Hi Dave,

Welcome to Permies.

Love this thread! Already updated my database with a couple I was uncertain of/hadn't considered.

I've sort of carved a niche out for myself as the local juglone expert, and in the process I've gained a lot of firsthand experience with our lovely native walnuts. Here's what I've personally tried  and witnessed so far that I haven't seen already listed:
-Allium cernuum
-Asarum canadense
-Chrysogonum virginianum
-Cimicifuga
-Clayonia virginica
-Dicentra
-Diospyros (also of note: the authors of Nut Growing Ontario Style claim that persimmons ripen two weeks earlier under the influence of juglone. Cannot comment on the veracity of this claim but very interesting to a northern grower like me)
-Fragaria vesca
-Geranium maculatum
-Hamamelis
-Helianthus tuberosus
-Lobelia
-Lonicera sempervirens
-Matteuccia struthiopteris
-Mertensia virginica
-Monarda
-Philidelphus
-Polygonatum
-Ribes
-Rosa setigera (so far not thriving, but surviving well)
-Rubus odoratus
-Sambucus
-Smilacina racemosa
-Solidago
-Symphiotrichum
-Stellaria media
-Tiarella cordifolia
-Ulmus rubra
-Viola

I recognize that not all of these are universally considered 'permaculture plants', but they all have their uses, whether food, medicine, groundcover, early-season nectar, etc.
Also, where's this wiki? And in the original post, when you say sorrel, do you mean Rumex or Oxalis (or both)?

Also, in the original post, when you say sorrel, do you mean Rumex or Oxalis (or both)?

Do black walnut trees have alleopathic effects on other plants ?

https://rex.libraries.wsu.edu/view/pdfCoverPage?instCode=01ALLIANCE_WSU&filePid=13333013240001842&download=true

I've read somewhere that mulberry will exude a juglone anti-toxin when planted near walnuts. I have seen mulberries growing quite happily near walnuts, and have seen a diversity of species thriving in the vicinity, so I am inclined to believe the claim, but don't have any scientific data to back it up.  

Peach trees seem to have problems under the shade of the old walnut tree...

About five or six years ago we planted two peach trees: one under, what is now, the drip line of a walnut and another about ten feet north of that.
The one under the drip line is pretty scraggly and has borne less than half a dozen fruits in a year. The more distant one produces very many large fruits, few of which end up being edible; they usually either rot on the tree or fall off before they're ripe.

Both suffered some critter damage to the bark the first year, which may be at play here. Also, being in the shade of the walnut during midday times could be a factor as well - they get good sun in morning and evening times

I'm cutting down the walnut to see if that helps, although, considering the comment above about the juglone concern extending beyond the drip line via root system, I'm a little dubious if it'll help. Time will tell

I've tried four different types of Elderberry near my black walnut trees after reading that they were juglone tolerant.  None of them survived more than a few months or so.   I read that tomatoes and peppers were tolerant, so I tried several of those one year.  Only one hot pepper plant (Anaheim) did well enough to harvest a handful of fruit from.  I got one small ripe tomato off a stunted plant, but that was it.  Most of them got decent sun, at least half day.  The hot pepper that fruited was on the south end and got the most sun out of that group.

Last fall I got a red raspberry and planted it on the southwest side of the black walnut trees, right about at the dripline.  It just started coming back this spring so I am hopeful.  I planted a black currant on the southeast side at the same time, which is starting to leaf out now as well.

I need a fruiting or edible groundcover for that area.   Would love to have cranberries or wintergreen, but not sure whether they are tolerant.  So far some "weeds" are popping up, one of which I believe is edible so I will let it grow and research eating it.  It is a bright green, very small leafy plant that I cannot recall the name of.  It's not sorrel.

On the lighter side, yesterday we took a tarp off of a pile of firewood that we hadn't gotten around to stacking last fall.  It was absolutely covered in black walnut shells that had been chewed into and the nut meats removed by the aggressive small squirrels that infested us a few years ago!  We now, after stacking the firewood, have about two heaping wheelbarrows full of nut shells to dispose of!  (Any ideas??)  

Time to get out the live traps and get rid of some little squirrels before they can get at my food plants.  Last year they chewed up an avocado tree in its pot on my deck, and stole the one pomegranate that grew on my little potted bush just before it was ripe.  They would pull strawberries and sit on top of my deck posts eating them, and invariably leave partially eaten gorgeous berries for me to find.  (I don't think they were sharing, more like taunting...)

Donna Lynn wrote:I've tried four different types of Elderberry near my black walnut trees after reading that they were juglone tolerant.  None of them survived more than a few months or so.   I read that tomatoes and peppers were tolerant, so I tried several of those one year.  Only one hot pepper plant (Anaheim) did well enough to harvest a handful of fruit from.  I got one small ripe tomato off a stunted plant, but that was it.  Most of them got decent sun, at least half day.  The hot pepper that fruited was on the south end and got the most sun out of that group.

I'm surprised by all of this. Both that the elderberries failed, and that you heard that nightshades are juglone tolerant - they're at the top of every list I've ever seen for juglone susceptibility. I wonder what other conditions might have led to the elderberries' demise; I've got a red one growing in the shade of an enormous walnut tree at a client's place, and if it weren't for the deer it would be enormous by now.

Donna Lynn wrote:I need a fruiting or edible groundcover for that area.   Would love to have cranberries or wintergreen, but not sure whether they are tolerant.

I wouldn't bother with cranberries or wintergreen; not only have I not heard of or seen their having any tolerance, they both like highly acidic conditions that you're not likely to see around a walnut. I'd recommend  Fragaria vesca, woodland strawberry as a groundcover and/or gooseberries and possibly goumi in the shrub layer for fruit.

Marvin Warren wrote:

Donna Lynn wrote:I've tried four different types of Elderberry near my black walnut trees after reading that they were juglone tolerant.  None of them survived more than a few months or so.   I read that tomatoes and peppers were tolerant, so I tried several of those one year.  Only one hot pepper plant (Anaheim) did well enough to harvest a handful of fruit from.  I got one small ripe tomato off a stunted plant, but that was it.  Most of them got decent sun, at least half day.  The hot pepper that fruited was on the south end and got the most sun out of that group.

I'm surprised by all of this. Both that the elderberries failed, and that you heard that nightshades are juglone tolerant - they're at the top of every list I've ever seen for juglone susceptibility. I wonder what other conditions might have led to the elderberries' demise; I've got a red one growing in the shade of an enormous walnut tree at a client's place, and if it weren't for the deer it would be enormous by now.

Donna Lynn wrote:I need a fruiting or edible groundcover for that area.   Would love to have cranberries or wintergreen, but not sure whether they are tolerant.

I wouldn't bother with cranberries or wintergreen; not only have I not heard of or seen their having any tolerance, they both like highly acidic conditions that you're not likely to see around a walnut. I'd recommend  Fragaria vesca, woodland strawberry as a groundcover and/or gooseberries and possibly goumi in the shrub layer for fruit.

Thank you for the advice.  When I first started experimenting with designing walnut guilds, I searched online for information.  Lots of it was conflicting!  So I just decided to try things I wanted to grow anyway that were on any of the tolerant lists, and see what happened.  I do have two new elderberries planted far away from any walnut trees, and this is their first overwinter so I don't know how they will do.  They both have a few swelling buds, so I have hope for them.  I love having elderberry syrup to head off winter colds and sore throats, so I will keep trying with the elderberries!

Midwest Permaculture put out an ebooklet on guilds, and it states that juglone can affect other plants up to 50% beyond the drip line of the tree.  Then it goes on to say that mulberry trees can be planted between a walnut and other trees that are not tolerant but within that 50% area, to help mitigate the effects of the juglone.  I'm mildly allergic to mulberries so haven't (and won't) try that.  I may try an autumn olive and a few pawpaw trees within the drip lines of some of my walnut trees.  I'll check into the gooseberries and goumi you mentioned too - I've never eaten any but I'm sure if I don't like them some critter or other will take care of them for me!

I did try wintergreen and cranberries in an acidic area of my yard where my blueberry bushes are, but they didn't survive long.  It may have been due to decaying roots of a pine that was dying and had to be cut down.  The blueberry bushes are surviving but not thriving despite good soil acidity.  Sorrel appeared and thrived there.

Bee Brode wrote:I've read somewhere that mulberry will exude a juglone anti-toxin when planted near walnuts. I have seen mulberries growing quite happily near walnuts, and have seen a diversity of species thriving in the vicinity, so I am inclined to believe the claim, but don't have any scientific data to back it up.  

I have mulberries naturally coming up all around my black walnuts. Incredibly healthy and vigorous - they even pop up inches from the base and thrive.

Donna Lynn wrote:

We now, after stacking the firewood, have about two heaping wheelbarrows full of nut shells to dispose of!  (Any ideas??)  

Make a small biochar kiln and biochar them. I wonder if extra biochar under and past the drip line would actually sequester some of the Juglone - or hang onto microbes that like to break down juglone - and actually help you with the problems you're having? I haven't had experience with this - maybe ask the question over in the biochar forum? ( https://permies.com/f/190/biochar )

Jay Angler wrote:Donna Lynn wrote:

We now, after stacking the firewood, have about two heaping wheelbarrows full of nut shells to dispose of!  (Any ideas??)  

Make a small biochar kiln and biochar them. I wonder if extra biochar under and past the drip line would actually sequester some of the Juglone - or hang onto microbes that like to break down juglone - and actually help you with the problems you're having? I haven't had experience with this - maybe ask the question over in the biochar forum? ( https://permies.com/f/190/biochar )

Very interesting idea!  I'd love to make some biochar.  I'll have to see what I can come up with to do that.  Then test it out in various areas to be sure it helps not harms.  Thanks Jay!

Ooh, Marvin, tell me more about Ribes tolerance to juglone. I've planted a black walnut about ten m from my cherished blackcurrants.

Marvin Warren wrote:
I've sort of carved a niche out for myself as the local juglone expert, and in the process I've gained a lot of firsthand experience with our lovely native walnuts. Here's what I've personally tried  and witnessed so far that I haven't seen already listed:
...
-Ribes
sally considered 'permaculture plants', but they all have their uses, whether food, medicine, groundcover, early-season nectar, etc.
Also, where's this wiki? And in the original post, when you say sorrel, do you mean Rumex or Oxalis (or both)?

Linda