Available in a rainbow of colors, the petunia (Petunia hybrida) is a popular perennial most often grown as an annual. With full sun and regular water, petunias will grow in any USDA hardiness zone. Petunias bring color to any garden, with flowers in shapes ranging from delicate funnels to wavy ruffles. In cooler regions, petunias are popular summer flowers that die off at first frost, and in warmer, more humid regions, they are used for winter and spring color, as humidity will cause them to die back.
This class of petunias provides the least amount of blooms but does offer a wide range of colors. Flowers are ruffled or wavy and are available in pink, reds, blue, white, pale yellow and some striped combinations. These petunias are sturdy and may grow to 27 inches high and 3 feet wide, according to the 1997 Sunset National Garden Book. Blooms are nearly 5 inches across. Some varieties, including Cascade, Countdown and Supercascade, are popular for hanging baskets, as the plants will--as the names imply--cascade.
Similar to the grandiflora series, the hybrid multiflora has a small flower, about 2 inches across, and is available in several colors, including bright yellow and cream. These petunias may have single or double blooms that are 2 inches across, and the plants themselves, which are more compact than other types, are often used in bedding or large plantings. Flowers on the Joy and Plum varieties have satin-textured blooms, while the Summer Sun has a bold yellow flower.
Resembling a dwarf version of the multiflora class, milliflora petunias grow to about 10 inches with blooms that are about 1 1/2 inches across. Used in bedding, these petunias are also a good choice for pots, window boxes or other small spaces. The Fantasy variety, which according to SouthernLiving.com debuted in 1996, is among the most widespread and blooms are available in pink, red, blue or ivory.