A customer of mine decided to do his own mulch. After he finished, I asked him if he had put any type of pre-emmergent down before installing the mulch. He looked very puzzled . He then says "Can you do that for me? My wife just hates pulling weeds." Ok, so now the 64k question---Is there anything out there I can put down on top of the mulch to help out with his inevitable weed problem? It looks like the mulch is only about two inches thick at the most. Thanks.