November's Flower of the Month

Petunia

(Petunia  hybrids and species)

 (All America Selections 'Opera Supreme')

I remember the old-fashioned petunias that grew in my garden when I was a child. Never did I have to plant these old, open pollinated strains. They came up with exuberance in every nook and cranny where seeds had fallen from the previous season’s crop. Flowers bloomed in magnificent profusion on vining plants in hues of purple, white, and pink. They perfumed the whole garden with their powerful fragrance. These wild petunias (Petunia integrifolia) were chosen as Texas Superstars because of their cold and heat tolerance and resistance to diseases.  

Today over 300 different varieties of petunias are available, so it is hard to know where to begin. The buyer is greeted with such terms as grandiflora, multiflora, floribunda, miliflora, and even hedgiflora. Trailers, doubles, minitunias, and supertunias further confuse the issue. Generally, the floribunda hybrids have medium-sized flowers with heavy blossom production. Varieties include the Celebrity, Primetime, and Madness series. (Series is a word that refers to a variety that comes in a range of colors.) The grandifloras include the Avalanche series. They tend to bloom early and have large flowers. Multifloras include the Wave petunias.

The Wave petunias offer several choices that boast greater heat and cold tolerance than many of the others. The original Wave series was introduced in 1995 when Purple Wave was designated an All-America Selection winner. Following closely on its heels were Pink Wave, Rose Wave, Misty Lilac Wave, Blue Wave and another AAS winner, Lavender Wave. Next came the Easy Wave series which are more mounding, and then the Tidal Wave group which can grow up to three feet tall if planted close together. 

From Australia come the Supertunias (P. axillaris), which are ever-blooming, long-lived, and available in a wide range of colors and growth habits. Trailblazer and Surfinia offer still more choices. Look also for the Kahuna, Supertunia, Surfinia, and Suncatcher series. To further cloud the issue, the Calibrachoa hybrids are sometimes called minitunias, but are in fact bellflowers. Cultivars are called Million Bells and Lirica Shower. One of the most gorgeous hanging baskets I have ever seen was filled with hundreds of terra cotta colored bellflowers. They are also available in dark blue, white, dark red, and yellow, and are reportedly hardy to 15°F.  

Petunias are usually cool weather plants for most of the South. In my garden, I find that they grow well in late fall and early winter and again in spring before the hot weather arrives. Most of us in the South can keep them growing vigorously all winter if they are in containers that can be moved to protected places in freezing weather. In my experience, they burn out during the heat of summer.

Many of the new hybrids, however, exhibit increased cold and heat tolerance and less susceptibility to diseases and pests. Petunias are heavy feeders and should be planted in rich, organic soil and fertilized regularly throughout the growing season. Pinching or cutting back the stems will generate growth and more blooms. A good layer of mulch will keep soil temperatures more constant and prevent rapid moisture loss. 

If you have not grown petunias in a while, now may be a good time to give them another try. Some of them may surprise you with their vigor, floriferousness and cold tolerance.