Viola riviniana ''Purpurea'' - Dog Tooth Violet''

This is a gorgeous violet with purplish-green foliage that forms a magnificent ground cover in difficult areas, such as under trees.  It produces small magenta-purple flowers in Spring and Summer - they are unscented but very pretty.  It does sucker and self-seeds but the more difficult the situation, the less it will spread.  I wouldn't be without this tenacious treasure.  Thrives in partial to full shade.  5-10cm x 30cm approximately.