Feverfew (Tanacetum parthenium)
This is apparently a potential invasive species. It's not on the state list, but the way that it colonized the garden bed in two years from a small patch of flowers was impressive. On the other hand, it's a very pretty plant.
I've heard that this is a medicinal herb, too, although I've never used it that way. A good plant to have if you're willing to pull out seedlings from that spot for the next several years.
