I am using Mazus repens 'Alba', and Ajuga, but my effort is new. Over many years I just used wood chips. The roses will be cut down to a foot in height, and the bases surrounded with wire cages and filled with oak leaves and pine needles, for Winter. How this will affect the Ajuga and Mazus is unanswered, as both are evergreen, here. I expect they will both make it and bloom, nicely, in Spring.