Yes they will grow all the way down if you give them a chance. I am sorry about the quality of the picture too. Creeping phlox come in a variety of colours as well. I have the bright pink, purple and white with a pink cross through the center of the bloom. I didn't amend the soil when I planted them. I needed a quick fix so it was straight clay when they were planted. I also have evergreens (blue rug juniper) planted in between the phlox. After this picture was taken I added some yuccas to the middle too so this year it is really full. I placed some rocks on the bare spots to temporarily stop the mud sliding.
Gardencrazy