Possible Duplicate:
How do I bake weeds out of my landscaping?
How to stop grass growing through landscape pebbles?
How do you best remove weeds that have infiltrated a weed mat covered with medium sized marble chips. I have a japanese garden, the weed mat was laid down by the landscaper about 6 years ago, covered with marble chips that are about 1/2-1"thick, some bare spots, and each year more weeds creek up through the mat and are impossible to pull out. Must I rip up the entire area and start again. He did kill the entire area with a chemcial before putting the weed mat down. Deer and debris from neighboring trees get on the marble chips.