They re available even at supermarkets. Choose whatever color pleases your eye. But keep an eye out for form, too. The New Wave series of petunias cover areas up to 4 feet across and are excellent as groundcovers or in containers. Work a spadeful or two of compost into the soil first.
Petunias do best in average, well-drained soil.
Plant in spring after all danger of frost has passed. Follow label directions, spacing anywhere from 8 inches to two feet apart. Mulch around petunias. This keeps their sticky leaves and flowers clean. Keep the soil at least slightly moist.