looks like ajuga

I forget the proper name but it might be chameleon plant. It does tend to take over if that is it.

louisiana girl is probably referring to plant linked below. I pray it's way overcrowded ajuga instead. That you can divide easily.

Here is a link that might be useful: houttuynia (sp?) - let's hope not

Looks like Ajuga to me also. It spreads, but not very aggressively. An occasional trimming will keep it looking neater next to the concrete.
Mike

That’s not houttuynia. I’d kill to have that instead of the incredibly invasive immortal destructive houttuynia...