A: Stones are good for decor but not for mulch under plants. My biggest objection to stones is practical. If leaves and straw fall on the rocks they are the very devil to keep clean! You’ll have to blow or sweep the site almost daily. In addition, if you change your mind in a few years, the rocks are almost impossible to remove. They seem to burrow into the earth and cement themselves in place. This latter concern might be avoided by covering the soil with landscape fabric before applying the rocks. My biggest objection, though, is that rock mulch doesn’t feed the soil like straw or wood chips would. Try the rocks if you like but keep my concerns in mind.