I have tried repeatedly to plant a hardy groundcover between rocks set into soil as a landing area for my water faucet area and in the expansion joints of my sidewalk. Here's what I've tried so far: various thymes, creeping pennyroyal, blue star creeper, moss, various low sedums. Nothing lasts beyond one season. Likely my biggest failure is to keep them well watered until they get established. Dandelions, buttercups, and grass seem to thrive in these areas and overpower whatever else I've planted. Any suggestions of a really hardy, low-maintenance ground cover that might adapt to these poor conditions?
