How long does black walnut toxin persist in the soil?
Any one have any idea how long the black walnut toxin lasts? I have three walnut trees in my back yard, grafted onto what I think
are black walnut bases. The trees on the top have died. The bases are sending up suckers. I'm thinking of trimming off the suckers.
In a couple of years, the trees should die off completely. Then I'll have three beautiful structures to support gorgeous, huge, rambling roses, ones I'm afraid to grow on the fence for fear they'll be too heavy. This will only work if the toxin fades away when the tree
finally dies. So, back to my original question. Does the toxin persist in the soil after it is no longer being produced, or does it break
down over time? And if so, how long does it take?