What is it?

Doing my long overdue fall cleanup / post-freeze assessment. This guy is back. I have it in two places.
Sad thing is that I'm not sure it's not something I planted on purpose. It kind of looks like strawberry, and I thought about seeing if strawberry would grow here.
But maybe it's blackberry. Or poison ivy. I have no idea! The stems were clumped, it had shallow roots (maybe an inch long?), the stems were rough but not exactly spiky, and I've pulled it out at last twice this year under my new "if I didn't plant it it is probably a weed that will take over if I don't rip it out" policy. (That policy replaces my "if it's green it's pretty" policy, which didn't work out.)
What is it??

(I'm looking at the three-leaved thing. The heart-shaped leaves are the vancouveria that I'm cutting back everywhere - it's done for the year!)