Oh no! I recently scrounged some bags of leaves. People leave them out for pickup in huge paper bags so I helped myself. I looked in one and saw WALNUTS, but figured that I could pick those out when I came to use the leaves. I never even thought about the leaves containing juglone.
Thanks for the wake up call!
Linda
Edited to add that I just looked it up, and juglone IS broken down by composting, so it's a relief that I can still use my big bags containing walnut leaves