There are many good fact sheets on the Web regarding juglone toxicity, but I'll attach a helpful one. It's worth noting that walnut leaves CAN be composted as long as you don't intend to use it right away.

Also the allelopathic chemicals come from just about all parts of the plant, including the roots and run-off from the branches and leaves.

Here is a link that might be useful: Click here for some good information

Thanks for the link, Rhizo-- it's a huuuuge help! Luckily my main garden isn't anywhere near the trees, but now I know that there are a couple things that I can grow on that beautiful sunny fence :D

I have a shade garden planted under Black Walnuts and it is thriving. I have many varieties of hosta, ferns, columbine. I had many others in there and don't know if the juglone killed them or if the hostas just took over.

melon, be sure to do some searching on your own, too. I'm sure that you'll find even more plants that are very tolerant of juglone.

Thanks for that website. I had done some research last summer and found that Impatiens were listed (didn't notice it on this site with a quick once-over). I planted some and they grew fantastic and added lots of color. I have found that Walnut roots grow for many, many feet (guessing, probablly 60 - 70 feet) from the tree. I was wondering why some roses were dying and in digging a hole, found walnut roots in it.