It is an alien species and according to the RHS is a pest at best and a threat to our native flora at worst. I saw quite a few clumps of it along the river bank when I walked the footpath on Saturday. And you must admit its rather a strange, almost unearthly looking flower. But it seems the bees and other insects don't mind it's looks or it's parentage. Lots were entering that inviting mouth to see what they could find!