Wave petunias (Petunia x hybrida) are spreading petunias that make a mass of color that lasts all summer. Although Wave petunias reach heights of just 5 to 7 inches, the plants spread out as much as 3 feet. Variations on conventional Wave petunias are available, such as Cool Wave, Shock Wave, Easy Wave, Double Wave and Tidal Wave.
When properly cared for, Wave petunias require no pinching to make full, bushy plants. Unlike conventional petunias which are upright plants growing from a main stem, Wave petunias grow outward from the middle, or crown of this plant. This growth habit allows new growth to spread and bloom over the old growth, developing a mound of vibrant color.
Unlike conventional petunias that require regular deadheading to keep them blooming prolifically throughout the season, Wave petunias require no deadheading. Since the flowers wilt and dry up, they fall naturally in the plant, and new flowers soon takes their spot. When the older growth is covered by mounds of new growth, blooms appear just on the stem tips of older growth.
Often, Wave petunias grow all season with no need for pruning. However, if the plants start to look forlorn, leggy and ragged in midsummer, it is fine to cut them back to about half their length. Water and fertilize the plants immediately after pruning to encourage healthy new growth.
To perform at their best, Wave petunias require 5 to 6 hours of daily sunlight. Wave petunias do best when a time-release fertilizer is added to the soil or potting mixture at planting time. Thereafter, apply a water-soluble fertilizer every two weeks. Water Wave petunias whenever the soil feels dry to the touch, but do not allow the soil to remain moist, as soggy dirt promotes decay and disease. Curiously, while Wave petunias tolerate slightly dry dirt with no adverse affects, the soil shouldn’t ever become entirely dry. Containerized petunias may call for daily irrigation during hot weather.