Crop Culture Report: Petunia Surfinia Summer Double Series

September 10, 2012 - 15:35

These heat- and weather-tolerant double petunias are compact and loaded with blooms to offer gardeners three seasons of color.

If you’ve sworn off growing double petunias, think again. Suntory Flowers has taken their performance to a new level with Surfinia Summer Double petunias, a new series that is a spinoff of the company’s Surfinia petunias. Compact plants flower profusely and early, presenting excellent coverage in a 4-inch pots and baskets. The series is uniform across three colors — Pink, Rose and White.

While double petunias are typically later than single-flowered, Surfinia Summer Doubles are the earliest to bloom in the double petunia category.

In the garden, Summer Doubles are heat and weather tolerant. Flowers remain double in 90-degree heat. While traditional doubles can get soggy in rain, the Summer Double flowers are smaller and tightly held to shed rain with ease. As the season progresses, new flowers emerge to bury old ones, reducing the need for deadheading. Gardeners enjoy three seasons of blooms from spring through fall.

Summer Doubles represent the most modern genetics in the Surfinia line. In terms of growth habit, growers can expect them to be similar to ‘Surfinia Deep Red’ and the newer Bouquet colors. Plants have a mounding, compact habit, even in the final pot size, which can be 10 inches or larger. In double petunias, you won’t find a nicer presentation in a 4-inch pot. Plants are compact and loaded with blooms. Keeping quality is excellent at retail and the high flower count is sure to stimulate impulse sales.

General Culture

For propagators, Surfinia is easy to root in three to four weeks on the bench. Pot rooted cuttings into 4-inch to 6-inch pots or hanging baskets. One liner per pot is recommended using a free-draining, open soil. Temperatures at this stage should be between 55 and 60 degrees Fahrenheit.

Crop timing for Summer Doubles is:
• 4-inch pots — four to six weeks with one liner and one pinch.
• 6-inch pots — seven to eight weeks with one liner and two pinches.
• 10-inch baskets – 10 to 12 weeks for 10-inch with three liners and two to three pinches.

For larger containers and baskets, plant liners in odd numbers – three or five.

Surfinia petunias will require pinching to encourage the right habit and breaks to get a bushy and spreading plant. The first pinch should occur two weeks after potting.

Irrigation & Fertilization

Keep growing media pH between 5.5 and 5.8. Overwatering will lead to root rot. A little-and-often regime is encouraged when plants are young. As they grow, Surfinia petunias become heavy feeders. Using slow-release fertilizer is recommended as they grow in addition to liquid fertilizer.

Controlling Plant Growth

Surfinia petunias respond to plant growth regulators. Apply B9 or other daminozide products at a rate of 2,500 to 5,000 ppm. A Bonzi drench can be applied at 1 to 3 ppm. Apply as needed. Surfinia grows rapidly in high light and high heat.

Pests & Diseases
Key pests to monitor are aphids, fungus gnats, mites, shore flies, thrips and whiteflies. Diseases include Botrytis, Phytophthora, Pythium, powdery mildew and Rhizoctonia.

About The Author

Delilah Onofrey is director at Flower Power Marketing, supporting Suntory Collection in North America. She can be reached at donofrey@gmail.com

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