I know this is an old thread but have a similar if not the same plant as a volunteer in my yard under a globe willow tree. I'm thinking it is a mulberry, most likely a Morus rubra, since the leaf is rough. I have a large mulberry tree in my yard and get quite a few seedlings from it but this is different than those. I will let it grow until next year to see what is happening with it but if anyone has further information then I would appreciate it.
If you would like pictures I can supply those also. Thanks
