I remember now! It's Phlox! Periwinkle (vinca) is more of a ground cover with lovely glossy green leaves. I planted about 100 little vinca plants in the front foundation bed of our house in NJ! They sure spread fast though, and I got a good deal on the little small plants from
Musser Forests. It's a great place to get plants if you don't mind starting small and waiting for them to grow and fill out, instead of getting huge landscape plants.