Nothing is as charming as a patch of Johnny-Jump-Ups poking their heads above the snow. Although violas are perennial, they are often grown like annuals because they do not perform well in an extended period of heat. USDA zones 4-8 can reliably plant violas as perennials. Other areas may want to use them as cool-season annuals. Violas will return in all zones by reseeding. Edible flowers are charming on salads and desserts.