Varieties
Within the petunia genus, there is great variety and most are sold as hybrids: single and double blooms; ruffled and smooth petals; striped, veined, and solid colors; mounding and cascading growth habits; and even some with fragrance.
Petunias
June 2, 2022
COLOR YOUR GARDEN
With Pretty Petunias
Color your garden with the wonderful world of petunias. These fabulous favorites open flowers in every color but brown. You can find blooms in pale pastel hues, black and even the botanically elusive blue.
Types
Multiflora petunias are the most durable and prolific. They have smaller but more abundant flowers and are ideal for summer bedding or in a mixed border (because they are more tolerant to wet weather).
Grandiflora petunias have very large flowers and are best grown in containers or hanging baskets (because they are more susceptible to rain damage). These large petunias often do not fare as well in the south because they’re prone to rot during humid, hot summers.
Floribundas are intermediate between the grandiflora and the multiflora groups. They are free-flowering like the multiflora varieties and produce medium-sized blooms.
Millifloras petunias are much smaller than any other petunias on the market. The flowers are only 1 to 1½ inches wide, but they are prolific and last all season!
Spreading or Trailing Petunias: These are low-growing and can spread as much as 3 to 4 feet. They form a beautiful, colorful groundcover because the flowers form along the entire length of each stem. They can be used in window boxes or hanging baskets.
Planting
Most petunia varieties prefer full sun, meaning at least six hours of direct sunlight on most days. But in the heat of summer, partial shade (especially from the strong afternoon sun) will help to keep them refreshed and blooming better.
Petunias prefer a light, fertile soil that provides good drainage. They can tolerate a variety of soil types as long as they are well-draining. Plus, they like a slightly acidic soil pH.
Watering
Petunias can take summer heat in even the warmest regions, but you’ll need to water plants consistently to keep the flowers coming. In landscape plantings, water spreading petunias, such as Wave or Supertunia types, a few times a week once summer heat arrives. These plants can grow up to a foot a day in ideal conditions, and they need sufficient water to fuel that intense growth.
Other petunias can get by with less frequent watering — maybe twice a week in southern areas and weekly in cooler northern zones.
Fertilizer
Spreading petunias have humongous appetites. Feed them weekly in planting beds and pots with water soluble fertilizer. Fish emulsion is a good natural choice. In containers, try a bloom booster fertilizer. Look up your specific petunia type online to learn if you need to remove spent flowers. With many of the newer petunias, plants are self-cleaning.
Pruning Tip
When planting young petunias, pinch back the stems to encourage more branching and a fuller plant. How far back to pinch depends on the plant. If it is a short, stocky seedling, just pinch an inch or less. But if the seedling is gangly, you can pinch back the stem by half.
Problems
Wilted Flowers or Leaves
There are a number of reasons for wilted petunia flowers or leaves, but most of the reasons come down to water: too much, or too little. Check the soil and if it’s not damp, water your petunias. If moist, ease up on your watering routine.
Leggy Stems
Petunias often develop leggy stems, but it’s easy enough to remedy: deadhead flowers regularly by pinching back. If this doesn’t help your petunia fill out, you can prune its stems back to 2 to 3 inches long, and as it regrows it will be less leggy.
Containers
You can purchase special trailing petunias, which will perform dramatically in containers. However, growing petunias in pots, regardless of their type, should not disappoint you, as long as you treat them right. Petunias in containers will need to be watered more frequently – as often as once a day.
Pests
Petunias have few serious insect or disease pests, though aphids and slugs can be an issue.
