Though I have heard about problems planting around Black Walnuts, I have not researched much and have instead just planted. I have some spirea - magic carpet and also neon flash inside the drip line in a location where they are able to get some sun. Also directly under it I have some varigated weigela. To the outside edge I have blue star juniper and a line of mums, a Knock Out rose, and a canna bed. Everything has done well. The cannas have been exceptional there. I was pleased because this was a very unsightly area when I purchased the home. I am very religious, though, of having raked up every single walnut or debris that the tree puts out. I figured there was probably a lot of undesireable stuff in these. So far, I have not had a problem. I planted this last year and today it still looks good. No guarantee on what you'll experience, but so far, so good for me!

I too have just gone ahead and planted anything I wanted under the walnut tree, and for the most part have had good success. A Therese Bugnet Rugosa rose has done especially well, and would make a nice hedge (but very thorny).

We have red prince weigela and the varigated weigela under ours and they are going crazy :) I don't know about the spirea, but in my experience they are very hard to kill

We have Wiegela, Golden Privet,and Dwarf burning bush growing within 25 feet of a black walnut without problems. As we have black walnuts all over our property, the only problem we have had is the shade produced by them or having little walnut trees growing everywhere! I know some of the potato/tomato family are supposed to have problems but we truly have never had any. Good Luck.

I wonder the same thing. I planted spirea And it has not done well. Nor has hydrangea or tree peony. I cut down 20 black walnuts but the roots still there of course. Honestly, i would not plant the spirea. I have tried 3 different types and they have not thrived and i guess I'm just going to remove them. Forsythia works but i wanted something different. Good luck.