There are four main types of petunia plants: Grandiflora, Multiflora, Milliflora, and Spreading (Wave). All four are readily available in series, which are groups of plants with uniform size and flowering habits. The only varying characteristic is the range of colors of different petunia flowers within each series.
Grandiflora are old Petunia Varieties that were produced in 1950s. They produce single or double flowers that each is up to 5 inches in diameter. Some grandifloras have a cascading or trailing form, making them well-suited for window boxes and hanging pots. Others grow in dense mounds reaching 12 to 15 inches tall. Their flowers may be pink, rose, blue, white, yellow, salmon or combinations of these colors in stripes. These plants are not very tolerant of heavy rain and can become scraggly at the end of summer if they aren’t pinched back. Although their flowers are impressive, Grandiflora petunias tend to produce fewer blooms than some other, smaller-flowered types.
Grandiflora petunias series include:
Multiflora petunias produce a large number of flowers, although the individual flowers are somewhat smaller than those of the grandiflora petunias. Each flower reaches about 2 inches in diameter. The flowers may have one or two sets of petals and serve as color accents in a garden bed. Multiflora petunias are more compact than other kinds of petunias and can withstand wind and hard rain better than grandiflora varieties. Multiflora petunias require pinching back when they reach about 6 inches tall. Because of their mounding habit, multiflora petunias are a better choice for garden beds than grandifloras and they work very well in containers.
Popular Multiflora petunias include:
Millifloras also referred to as hybrid millifloras, are dwarf plants that usually grow no taller or wider than 8 inches.They produce flowers in abundance, but their flowers are smaller than those of other varieties, usually only about 1 1/2 inches in diameter.They require no pinching back or pruning, growing naturally in a compact form. Milliflora petunias produce flowers in most colors except yellow. They are excellent choices for containers, hanging baskets and window boxes.
Milliflora petunias include:
Ground Cover or Wave Petunia
Ground cover petunias, also called spreading petunias or Wave Petunia, grow only 6 inches tall but can spread more than 4 feet in one growing season. They thrive on water and weekly fertilization. These plants work well as a ground cover but also in window boxes, cascading over walls and in hanging baskets. They do not require pinching back, but removing their spent flowers can make them look more attractive than they would otherwise. Flowers on Wave varieties are pink, lilac, red, rose, burgundy or purple, with some flowers decorated with darker, contrasting stripes of complementary colors. Wave petunias make wonderful groundcovers and trailers for containers.
Wave petunias include:
- Easy Wave
- Shock Wave
- Double Wave
- Tidal Wave’ series