I purchased a crape myrtle tree at a garage sale. When I went to re-pot it, it had a "little" tree growing in the pot with it. When we took them out, we discovered the root system of this stow-away was taking up most of the bucket! Now I want to know what it is.
We're seeing pinnately compound leaves here, which Juglans do have. It's not clear in the photo whether the whole leaves are opposite or alternate.