Hit Them When They're Down

Not the most sporting tactic, but when dealing with Japanese knotweed (Fallopia japonica), certainly the right thing to do.

Japanese knotweed completely blocks light from getting to the ground layer, so that nothing but it lives under its canopy. In the fall those canes die back exposing open ground. The dead canes of Fallopia protect its rhizomes from the worst of winter frost and freezing. By carefully removing and burning the old stalks and leaving the ground open, you will let mother nature work on these invaders who come from a client that is not as extreme as Wisconsin. If possible, burn the canes onsite to eliminate the possibility of spreading the infestation.

While winter will not kill Japanese knotweed, it will weaken the plant making herbicide treatment in the spring more effective.