Black oak and juglone poisining

[Guyz-N-Flyz]

I think my uncle received a load of black walnut leaf mulch; consequently, his asparagus, Brussels sprouts, cucumbers, tomatoes and other veggies are dying.

Is there anything that will neutralize the affects of juglone toxicity, once he removes the offending leaf mulch?

TIA,

Mark

[paghat]

Composting breaks down the juglone, so if you mix the leaves with soil & keep it moist & add some nitrogen to speed up the process it will take care of itself at the speed of composting, even without entirely removing the leaves.

Since you indicate that your uncle will be raking out the walnut leaves, that'll speed up the process dramatically. He can follow the removal with deep watering now & then to flush any lingering juglone deeper into the soil, where bacteria will take care of it before too long. Presumedly he won't be planting any new veggies this time of year anyway, & the area should have repaired itself by next spring's planting time. He's not committed any end-of-world catastrophic garden booboo, it's something gardens can pretty much repair on their own.

You say, however, "I think" it was black walnut -- if no one's sure there were walnut leaves involved, there could be some other problem. I mulch with fallen leaves of chokecherry & sweet cherry & plum trees which all have juglone & this does't bother the plants at all, not even the azaleas which can be juglone-sensitive, but of course the concentrations are a fraction that of walnut, & I don't use these leaves for anything as senstive as tomatoes.

-paghat the ratgirl

[Pam - gardengal]

This is pretty interesting............I was not aware that juglone was present in any plant outside of the Juglandaceae and not even present in very high concentrations of most members of this family outside of the Juglans genus itself. Since I can find no references which address this phenomenon in any Prunus species, I'd be interested in being directed to a source or link which discussed this.

pam - gardengal

[Guyz-N-Flyz]

Thanks! I sent your reply directly to my uncle.

No we aren't sure, but where we live is plentiful with black walnut trees. I am only guessin', and my uncle is havin' a soil test done, though I believe he will take your advice regardless. He has worked very hard on his veggie garden and the asparagus is his trophy--so to speak. Dick is around 77 years of age and his veggie garden and fishin' are his greatest hobbies. Gardenin' is fairly new to him, but he has taken to it like a duck to water, so I imagine he doesn't really need my assistance; however, he isn't familiar with the availability of instant info via NGs. You have been most kind and I thank you very much!

Mark

[Guyz-N-Flyz]

Here's a little something:

if you do a Google search you will find more than you ever wanted to know.

The reason that black walnut and juglone came to my mine was because of an article I once read about black walnut shavin's and horses and cattle. From there I learn that not only were the shavings poisonous to stock animals, but that thee reason my tomatoes were doing so poorly was the 50' black walnut tree on the end of my veggie garden. I'm told by mountain folk that walnuts were placed in burlap bags and placed in streams to catch trout--many years ago. The toxin apparently paralyzes the respiratory system of the fish and they float to the surface?

Mark

[S. M. Henning]

All species of the walnut family produce juglone. Black walnuts have the highest concentrations. Relatively small amounts are found in butternut, hickory, and pecan. Most toxicity problems are caused by the black walnut. paghat's recommendation is right on.

In the meantime you can plant such veggies as: corn, beans, onions, beets, and carrots.

Avoid: asparagus, cabbage, rhubarb, tomatoes, potatoes, peppers, and eggplants.

[paghat]

Good catch, & wouldn't that explain why it doesn't bother the azaleas that get chokecherry leaves as mulch. Just muddy-thinking & quick-writing relying too much on an aging memory. It is of course cyanide-related toxins in the roots, leaves, & fruitstones of the trees we have whose leaves we use for mulching. The cyanide exuded from roots functions as a growth suppressant to give these trees an edge over competing plants in the immediate vicinity, the function also of juglone, but I've never seen any negative effect from using the leaves.

-paggers

[Frogleg]

In my experience, black walnut leaves are quite ephemeral. That is, they don't even last long enough to be raked, much less piled up and/or transported for mulch. Your uncle's problem may be something entirely different.