I have a bunch of this stuff growing in the corner of my property. It dies back in the winter and comes up every year. It has large tuber like roots and I keep cutting it back and it keeps growing back very quickly. It seems to get 4 feet or so wide and about the same tall. but probably could get bigger if I wasn't cutting it back. I bought this home last year and noticed it growing out back where the previous owner seemed to pile all their leaves.