It sounds like it is not hardy enough on Dave's Garden. I have a weed viola that spreads a lot by seeding and has purple flowers and heart-shaped leaves but don't know the name. Labrador violets have been the best for sticking around of the labeled violets I have bought.

Note that the so-called Labrador violet, with purple leaves and blue flowers is Viola riviniana 'Purpurea'. The true Labrador violet is a tiny thing native to the far north, perhaps not even in cultivation.

The local weed with green leaves and rosy flowers, often partly faded or bleached while still open is believed to be V. riviniana. Like the purple cultivar it may sow itself where not wanted. My neighbors to the south once had a fine big display of it, in their lawn.

Perhaps the patch is still there.

Beware of Labrador Violets! They spread everywhere, into the lawn, through the dry gravel under our eaves -- I can't imagine why anyone would plant them. They are one of the worst weeds in my perennial bed.