JuneOntario said: I would never have planted so many thymes if I had known they would spread so well...
It depends entirely on what your image of a rock garden is, and on what plants you want to grow and how... My own perspective is that if my whole yard was rock garden, I might have thymes in it but they are generally rather overly vigorous for the small rock garden, if you want to maintain space for a variety of less-dominating plants. (Fortunately, they do very well here outside the rock garden.)
