July 2014

Crop Culture Report: Bounce Interspecific Impatiens

This year, Selecta introduces all-new genetics of interspecific impatiens for a great opportunity to grow and merchandise a shade product with confidence. Bounce is highly resistant to Impatiens Downy Mildew, making it the best replacement option for spaces where I. walleriana has failed in the past. Use compact Bounce for hanging baskets or patio pots, and use more vigorous Big Bounce in the landscape or large-size containers.

Unlike New Guinea impatiens, Bounce has the walleriana habit and flower count, growing wide without apical dominance. It truly fills growers’ and retailers’ needs for a shade alternative. And as the names imply, watch it “bounce” back after wilt or complete dry-down without losing blooms or buds. 

For 2015 retail sales, Bounce is available in several top-selling colors: Cherry, Lavender, Lilac, Red, Violet and White.

This article shares some growing and culture tips for excellent-quality interspecific impatiens for shade garden confidence.

Rooting Guidelines

To root Bounce, we recommend a cell size of 25 mm. No rooting hormone is needed. Place it on a mist for an average of six to nine days. Reduce the mist starting day 5, careful not to overwater.

An early PGR spray is recommended. Cover the plants and avoid run off as much as possible. For vigorous products, the first application should be done about seven to 10 days after sticking and the second is when needed (testing before use). Average propagation is four to five weeks. No pinch is needed.

Rooting & Finishing

The best results are achieved if media with the correct pH is used starting with propagation. Aim for a pH of 5.8 to 6.2. For fertilizer, start with low concentrations after roots show and increase with plant development to the recommended levels: 175- to 225-ppm nitrogen.

Water management in rooting and finishing is half the success and the best way to prevent root-bound diseases, improve performance and control plant quality. Avoid drying out Bounce or overwatering the substrate as this will affect plant quality and finishing time. The root system will suffer when conditions change from one extreme to the other. “Growing on the dry side“ means letting the substrate become dry (substrate color turns light brown and substrate starts to separate from the pot edge) before watering.

Finishing Guidelines

During rooting, keep soil temperature measured in the liner at 70° F until cuttings are well-rooted. After planting the liner, keep temperature up until roots have developed nicely. Afterward follow recommendations: 68 to 79° F / 59 to 64°F .

The use of “Cool Morning“ treatments will improve plant quality, flower and foliage color. It will also improve the plant habit and harden the plants. Lower the temperature by 8 to 12° F two hours before sunrise until two to three hours after sunrise. Start treatments after plants are rooted in, well-branched and cover the media (reach the pot edges). To avoid delayed flowering, keep the average day temperature under a close watch, and if necessary, increase night temperatures. Finishing of the crop depends on the average day temperature, and positive or negative DIF methods as well as “Cool Morning” can be used to improve plant quality.

No need to pinch after transplant. Light levels should be maintained at 4,000 to 9,000 foot-candles.

Plant growth regulator recommendations at this stage: Bonzi 5-25 ppm (spray) or 1-2 ppm (drench), B-Nine 1,500 ppm (spray).

Inspect for pests and fungal diseases: thrips, aphids, mites, INSV, Botrytis and Pythium.

Crop Time

4- to 5-inch Pots, Quarts :