I found some pics and I think it is mugwort. UGH. Another impossible to kill weed, along with my creeping charlie....

Yes, mugwort is your varmint here. My neighbor and I got rid of our large patch of this crap by digging down as far as we had to with garden forks to get as many of the roots as possible, and then pulling the stragglers up immediately as soon as they surfaced, to exhaust the remaining roots.. It is a pain in the neck but it can be done.

Perhaps Herb Robert, also known as Stinky Bob -- smell a crushed leaf.

No. This is definitely not Geranium robertianum. Mugwort looks right.