where are you?

I'm just outside Richmond, VA. Zone 7b.

Do I see spines on that stem? If so, it's a greenbrier, Smilax sp.. Leaves don't look like the usual round leaf greenbrier, might be laurel-leaved (laurifolia) or red-berried (walteri).

Definitely spines. I think you're right. I'd better get that stuff out before it starts spreading!

Thanks so much.

That may be growth from established tubers (or one really big one,) Doesn't look like the seedlings I get, but there are quite a few species of Smilax.