I have read sev posts here abt "rogue" annuals (chickweed, etc) that come up after a clean planting. I had a bunch of this (Draba verna) come up this season. Comments, please, Joe, Lady, All?
i get this too, and in fact, any place where the ground is bare, they come in droves. the worst time for me is the spring, though, i noticed this weekend it has infested the border of my vinca minor.
this year i was planning on trying to use some pre-emergent...hit it a few times. i am particularly worried about this as i am in the middle of putting in a ground cover of liriope -- but i will use wood mulch to help the ground retain moisture until the liriope takes over.