Wave petunias are any of five varieties in a series known as “Ride the Wave.” Developed in Japan and introduced to the United States in 1995, they are marketed here by Ball Horticultural Company. Cascading petunias may be any of several cultivars, and you may find them at nurseries and gardening centers under trademarked names such as Supertunia or Surfinia, both marketed by Proven Winners. Cascadia petunias, developed in Israel, are quite difficult to locate in the United States, even through online retailers.
Wave petunias grow low to the ground, reaching only 4 to 6 inches in height and spreading from 3 to 4 feet. If planted 12 inches apart they grow together, providing a flowering ground cover. Cascading petunias, on the other hand, have a trailing growth habit. They typically grow 12 to 18 inches in height. Planted in a hanging container, the tendrils may hang up to 4 feet in length.
Wave petunias are mid-season bloomers; the blooms typically last until the first frost. Cascading petunias bloom early in the season. Some cultivars may persist through the entire growing season while others are finished by mid to late summer. Neither Wave nor cascading petunias require deadheading, a quality known in the greenhouse floral industry as self-cleaning.
Both Wave and cascading petunias come in a variety of colors. At the time of publication, there are six Wave petunia colors from which to choose: white and various shades of pink and purple. Cascading petunias bloom in a larger variety of colors. Flower sizes vary according to cultivar, from tiny to quite large. Wave petunias are single, although there is a variety in the series, Double Wave, which blooms in double flowers. Cascading petunias offer more double varieties than the Wave collection.
The Wave petunia is also known as “spreading petunia” and is best utilized in the ground where it can spread and cover garden beds. Cascading petunias, on the other hand, are ideal for container plantings. Some varieties tend to be aggressive and shouldn’t be mixed with other container plants but all look stunning spilling over the side of a hanging basket or window box. Some varieties of cascading petunias bloom better with a half-day of shade, so check the card that comes in the plant’s nursery pot for care requirements.
Wave petunias require more fertilizer than cascading petunias. In the greenhouse, they are provided fertilizer during every third watering. An abrupt change of schedule, upon bringing them home, may limit the amount of flowers the plant produces. Ball Horticultural Company recommends using 1 tablespoon of liquid 10-4-3 fertilizer in a gallon of water to water the Wave petunia throughout the season. Every seventh irrigation should be with plain water. Supertunia and some of the other cascading petunias typically require fertilizer every two weeks in May and once a week in June.
Harden off both types of petunias when you bring them home. Retailers are advised to keep them in the shade to avoid having to water too frequently, so they aren’t used to the sun. Place the petunias in the sun for two to three hours on the first day and then place them in a lightly shaded spot. Gradually increase the amount of sun they receive over the course of a week until they are in full sun all day.