The side of our yard has a slight slope and when it rains everything wash down to the gate & leaves a muddy mess. We planted a few plants, put some stepping stones and put down mulch. It looked wonderful & got rid of the mud. NOW THE PROBLEM. We have had more than our normal amount of rain & storms this year, that washes the mulch down. Is there something we can put on the mulch to make it stable? Or some other solution to this problem? I've been going out and raking it back up.