Petunias (Petunia spp.) are one of the most popular garden flowers for both borders and containers. They are fast-growing, prolific bloomers, and you can find them in just about every color but true blue. Petunias have wide, trumpet-shaped flowers and branching foliage that is hairy and somewhat sticky. Within the petunia genus, there is great variety: single and double blooms; ruffled and smooth petals; striped, veined, and solid colors; mounding and cascading growth habits; and even some with fragrance.