Ask-a-Dave's-Gardener: Pre-emergent help!, 1 by Sierragardening

Sierragardening wrote:
Hello! We have 2\' round mounds of ornamental grasses that soon will be removed. They seem to emit silver dollar sized seedlings each year that literally are taking over my flower beds (thus they are being removed)..our landscapers suggested using Caseron as a pre-emergent but this chemical prohibits new planting of any kind for a year! I have bulbs and Iris on order..is there another product I can use that will keep these stubborn grasses at bay but allow new planting?