I use Preen and it makes a huge difference in my small rock bed along the driveway and along the edge of a flower bed. It won't get rid of the weeds that already exist, only stops new seedlings from emerging. Works like a charm and I stock up when it goes on sale at Lowe's. I used a pre-emergent on the front lawn for the first time in October. Time will tell if it helps. What doesn't help is the neighbor who doesn't maintain his lawn.
I get his moles, too!
