I was wondering what techniques you guys use to help prevent weeds in mulch beds. I currently use preen in my mulch beds but lets be honest I might as well be throwing down weed fertilizer. I have primarliy been installing landscape rock with weed barrier to help prevent customer complaints in peak working times. I am looking to start installing alot of mulch as a ground cover due to jobs i am getting on lakeside properties. Is there a spray/ granule that is available to help me with this problem?