PLANTS VALUABLE FOR USE IN ROCK GARDENS, IN JAPANESE GARDENS, AND IN WALL CREVICES : Page 345
Perennial Flax Hoary Speedwell
Lychnis viscaria splendens * Veronica repens
Ragged Robin Creeping Speedwell
Mitchella repens Vinca minor
Partridge Berry PeriwinkleViola (various species)Violet
*Plants especially well adapted for use in crevices of walls and paved areas.