Sweet white violet (Viola blanda)

Native Perennial grows up to 8" tall, blooms April -May with white with purple accent 

Prefers:  Part Shade, Wet - Medium Soil

Low maintenance, great ground cover. Spreads by runners to form large carpets in the wild

Provence: Wild harvested in on my Property Pepperell, MA

If you have a rabbit problem you could use these as it is one of their favorites, so they don't eat your other plants.  They love these and they can withstand munching and mowing.