This is the idea I mentioned about using broken pottery. The color is nice here, however, consider using thyme. It is edible and beautiful and there are varieties that are evergreen. I've also used oregano as it "spills" into an herb garden. Fun!
'Marzipan' Phlox.. The marzipan phlox, which is also known under the beautiful name Star balm is a gorgeous ground cover. From a strong pink, lily-like bud, a pink-white flower a beautiful fragrance of marzipan exudes especially in the early evening hours and as night unfolds.