Bobert, it is in the parsley family - home to carrots and Queen Anne's Lace as well as water and poison hemlock. Wikipedia cites it as being highly phototoxic - a very noxious plant - and we all know how readily parsley family plants self-sow.    I'm just hoping that like Angelica, it doesn't like heat and so will be unlikely to migrate down my way over time.

Thanks for the heads-up, maeve.