This is a true groundcover with dense, ground-hugging foliage that steals a wider space for itself every year. The flowers are held a bit awkwardly atop long, bare stems, and the petals seem prone to burning even though mine gets some afternoon shade. Still, the mass effect is eye-catching. Bluestone Perennials recommends planting in mostly shade, which is probably a good idea.
This year, my plant started blooming in late April.