It first showed up 3 years ago and I didn't notice it till it started to bloom. It has a color and growth habit much like lambs ears but not so soft and fuzzy. It reseeds all over the yard now and is blooming in both sun and shade. It does not seem to have a scent.
Could be Lychnis flos-jovis (Flowers of Jove) originally from the European Alps, and low growing silver-grey foliage and pink to purple flower; or its larger cousin L. coronaria, Rose Campion, which is lighter grey and has larger single flowers in white or magenta.