Stay the fuck away from those. Phototoxic weeds are no joke.

In all seriousness, there’s a list of plants EU nations are supposed to weed. I think they do as much as they can for plants like Giant Hogweed (mostly because they tend to hurt children and people who don’t know about their properties)

In the case of Japanese Knotweed, they have basically given up, so it just flourishes everywhere.