Clematis virginiana invasive?
I'm trying to find more information regarding the native vine, Clematis virginiana. I have had 1 vine for 2 years growing on an obelisk, and this year I seem to have them popping up all over in the same area. I mean, it's really all over in there and also popping up in what little turf there is left (which is no big deal as any turf left is all going to go away) in the front of this area and between this area and another area. Is this vine considered as an invasive vine? Information seems to vary regarding whether or not it is. I had planned on giving a friend a piece, but now I'm not sure if I should or not. Any suggestions or advice would be appreciated!