The petals leaves on the Blue Violet are among the tastiest of the edible flowers.  They go well in salads and are nutritious.  In addition to its showy blue-violent flowers, this plant features heart-shaped leaves, makes a great groundcover and provides early pollen for bees and other flying things.
Height: less than 1 foot
Blooms: blue flowers show in spring and persist through summer
Conditions: well-drained soils in full sun to part shade