Sweet Violets (Viola odorata) begin blooming in gardens here in Tucson, Arizona in the very early spring, and these lovely flowers are in full bloom here by mid-February.
Sweet Violets were introduced here from Europe, and these adaptable plants can now be found growing wild in many areas of the US, including Arizona, but I haven't yet found any wild-growing Sweet Violets in the Tucson area (too dry).
These hardy perennials are easy to grow and prefer regular water, organic soil, and afternoon shade. Sweet Violets can be used as a groundcover in shady spots, and they eventually spread to form a dense carpet about 4 to 8 inches (10 to 20 cm) tall.
Sweet Violets have a long history of medicinal and edible use. The lovely, violet-colored flowers can be candied and used to garnish wedding cakes and other fancy desserts. The flowers can also be added to salads to give them added color. While the leaves are edible, they are a bit tough and bland, so they are generally not used in salads.