Apparently most of the native plants do fine with black walnut. Not the columbine. Hostas apparently love it and it kills a lot of weeds. If allowed to compost six months, nothing will be bothered by black walnut mulch. Most annuals do okay with it, too.
So I should mostly be okay with what’s been spread already. The offending chemical is called juglone. The internet can be amazing sometimes!
I have several VERY large black walnut trees in my yard and they have to be about the most toxic thing I know. Years ago, when we first moved into our present home, I had parked my car under one of them and the sap started to peel the paint off. I’d heard tell that the native Americans used the nuts to fish…dump a bunch in a pond and watch the fish float belly up. My walnut trees have killed off a variety of landscape projects. I have to move my compost pile away from the garage which is located under one of the trees. The nuts roll off the roof in the fall into the compost pile and taint it…have found out from personal experience to only use the compost for fill.
Just sayin’…I wouldn’t try any project involving black walnut products and expect it to successfully grow.
Oconto...the birthplace of western civilization:)
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