Gosh, this is a hot topic. Never encountered the stuff myself although I've been to the Himalayas several times. Notifiable pest here. They have huge rhodedendron forests there and they are considered pests here. Also huge cannabis plants too, growing wild. Illegal here, but made a nice wine out of discarded stems left in shared greenhouse once. Ground elder was introduced here as a food plant and I have encountered that. Gets everywhere and hard to control. Neighbours complained about 'triffids' which invaded their garden. Turned out to be jerusalem artichokes: edible but make you fart a lot. All a matter of perception, really.