It can be an aggressive spreader in the right situation and if you live close to a natural woodland, it can escape and colonize, perhaps outcompeting native plants. So some care should be taken when selecting and planting. But other than that, I would not consider it invasive in my shady zone 8 garden. It spreads nicely and wraps around other, larger plants, but it plays well with smaller ones, also. It hasn't smothered hellebores, hostas or ferns and it even allows woodland ephemerals like anemones and trilliums to emerge and push through. It's been in place for more than 10 years and if it was going to smother and kill all the other plants in the area, I'd think it would have done so by now :-) It is also very easy to remove if it grows where it's not wanted.