Oxford Ragwort came here from Sicily in about 1700. It's very toxic to animals, and a small amount getting into silage can cause irreversible kidney damage. Farmers are obliged by law to get rid of it from their pastures (but we see it everywhere here in Norfolk) It is a habitat/food for the Cinnabar Moth caterpillars however.

Giant Hogweed just sits there. If one doesn't touch it, it does no harm. It doesn't run about chasing people. One might as well command that all adders are exterminated, and all yew trees uprooted and burnt. Children should be educated about these things.