Petunias have been one of the most popular bedding plants for many years, available in a wide range of size, form, color and diversity of use. The compact multifloras or floribundas look great when used as edging in perennial borders or at the ends of vegetable gardens. Petunias are successful accents to window boxes, hanging baskets or container plantings. The trailing or cascading types combine well with many other annuals. Another bonus is the use of petunia as a cut flower. Cut the flowers, leaving short stems and place in a small vase or flower ring. Blooms will last four to six days and add a light fragrance to the room. The flowers can also be successfully pressed, either whole or with individually pressed petals.
The petunia is a member of the nightshade family, Solanaceae, which includes tomato and pepper. Discovered in the mid-1700s and early 1800s, petunia has its origin in South America, where the first ones were lanky with small flowers in just two colors, purple and white. It would take the diligence of German and English plant breeders to develop the garden petunia of today. The first fully double-flowering petunia was introduced in 1934 by the Sakata Seed Corp. of Japan. It was recognized that year by All-America Selections. Genetic research has continued over the years, resulting in enhanced attributes including varieties with larger flowers that weather rainstorms better, more compact plants with better branching habits, increased disease and insect resistance and more unique colors. Today, there are five main types available including Grandiflora, Multiflora, Spreading (or Wave) and Supertunia.
• Grandiflora – oldest form developed in the 1950s. Blooms measure up to five inches across. Best in cooler climates without excess humidity or moisture. Intolerant of heavy rain and requires deadheading.
• Multiflora – smaller plant that is the best choice for adverse conditions, especially hot, wet spells and windy conditions. Blooms all season with an abundance of flowers with a wide color range. Single multifloras are best used in mass plantings or borders. Double multifloras are best in containers and window boxes.
• Milliflora – introduced in 1996 by Goldsmith Seeds, plants are about 2/3 the size of regular petunias. Plant is low maintenance requiring no deadheading.
• Spreading or Wave – Low growing petunias under 6 inches in height spreading up to 4 feet, introduced by PanAmerican Seed. Plant is perfect choice for hanging basket or annual ground cover. Fairly resistant to heat and humidity. Flowering diminishes in prolonged heat as well.
• Supertunia – Part of the Proven Winners lineup, this weather tolerant plant is grown by cutting and not by seed. It is a vigorous grower and heavy bloomer. It requires consistent watering and fertilization to keep it at its peak.
I consider the Supertunia petunia one of the best flowering annuals for our climate for spring into early summer and in the fall. In the spring, I look for hanging baskets as soon as they become available at local garden centers or home improvement stores. The plants will bloom from spring to fall, depending on the site and soil, without quitting or requiring deadheading. The broad color palette offers a choice for every taste. The blooms attract both butterflies and hummingbirds. Supertunias look fabulous in large containers, but they also do well in hanging baskets and when planted directly into the landscape.
This year, I purchased hanging baskets in early April. I brought them home and carefully removed the plants, transplanting them into a favorite large planter which I constructed using leftover Trex from a deck project. All my containers are filled with a good quality all-purpose potting mix such as Black Gold, Miracle-Gro, or Proven Winners. My site location gets 6-8 hours of sunlight in the morning and early afternoon. I am considering placing a light trellis over my Trex planter this year as it gets more afternoon sun than petunias can handle in our high heat and humidity. It will be the first attempt in a long time to keep petunias throughout the summer. With only $40 invested, it is worth a try.
Here are some tips from Proven Winners for keeping Supertunias looking their best.
• Plant in a site with at least six hours of direct sun but try to find a spot with morning sun rather than afternoon sun. If you can provide filtered shade in the afternoons, that will also work.
• Provide consistent moisture. These plants are heavy consumers and soil can quickly dry out. A drip watering system can help keep soil consistently moist.
• Feed your plants often. Petunias are hungry feeders. Feed them often with a water-soluble fertilizer every third watering. You can supplement with a slow-release encapsulated fertilizer such as Osmocote.
• Prune lightly in midsummer, cutting off no more that 20% of the plant. It will cause the plant to be without blooms for the next week, but the flowers come back quickly. Follow up with a late summer or early fall trimming to keep Supertunia blooming into the fall months.
Gardening is always an adventure. Over the years, I have moved away from in ground plantings of annuals to container gardening. It’s a low-cost method of gardening that allows for a great amount of experimentation where “mistakes” can be replanted without a great amount of effort or cost. If my attempt to keep Supertunias blooming through the dog days of August and September fails, I can replant! There is always an alternative solution and really no excuse for not having year-round flowers in coastal Georgia!