February 2019 Culture

Culture Report: Argyranthemum Grandaisy Series By Delilah Onofrey

Why settle for a standard argyranthemum? Grandaisy is a new intergenerichybrid that produces larger plants with flowers twice the size! Bred by Suntory Flowers through its partnership with Bonza Botanicals in Australia, Grandaisy is a cross between two genera — argyranthemum and ismelia, commonly known as tricolor chrysanthemum or tricolor daisy. This is where the great colors come from. This highly advanced intergeneric cross is a triploid hybrid and protected by a utility patent.

Hardy to Zone 10a, Grandaisy is an annual in most climates. It produces a tough bushy plant with a mounded habit and is free flowering. Plants reach a height of 18 to 24 inches with a spread of 18 to 24 inches. Full sun is recommended.

Grandaisy likes it warmer than a standard argyranthemum and will continue to bloom through summer in Northern climates. Grandaisy isn’t recommended as a summer item for the South.

In last summer’s garden trials at Penn State University, ‘Grandaisy Yellow’ was named “One of the Best” and “Best of Species” with a 4.7 score out of 5 points.

SALES WINDOW

Produce for early spring through peak spring sales. Growers get a big return with just one cutting per gallon pot. Container suggestions are 2.5 quart and 1.5- to 2.5-gallon planters. Pair with premium patio pots to maximize the price point. Grandaisy is not recommended for 4-inch pots.

Colors include Red, White, Yellow and Pink Halo. New for 2020 will be a Dark Pink and Red Improved. The Red has been improved for color retention and showier habit.

Consumers are crazy for daisy flowers and will love the vibrant colors and full, vigorous plants. They are perfect for Easter and Mother’s Day in decorative pots. Merchandise out front and on endcaps for high-impact displays.

CULTURE NOTES

Crop times:
• 6-inch pot (one liner) – seven to 10 weeks, no pinch
• 10- to 12-inch pots (three liners) – nine to 12 weeks, no pinch

Propagation:
Store cuttings at 40 to 45° F for up to 24 hours if planting will be delayed. Stick cuttings in a substrate with a pH of 6.0 to 6.5. Recommended cell sizes are 50, 72, 84 and 105. Rooting hormone is not required.
• Mist for four to seven days. Average propagation time is three to four weeks. Avoid water stress.
• Maintain air temperatures of 70 to 75° F during the day and 68 to 70° F at night. Substrate temperature should be 68 to 75° F.
• Maintain light intensity of 500 to 1,000 foot-candles.
• Begin foliar feed of 50- to 75-ppm nitrogen using 15-0-15 NPK liquid fertilizer. Keep substrate moist so that water is easily squeezed out of it but not waterlogged.
• Transfer cuttings to Stage 3 in five to seven days, once 50 percent of the cuttings begin rooting.

Stage 3 – Root development:
• Maintain substrate temperature of 68 to 75° F. Recommended air temperatures are 70 to 75° F during the day and 68 to 70° F at night.
• Increase light intensity to 1,000 to 2,000 foot-candles as cuttings begin to root.
• Begin drying out substrate once roots are visible.
• Fertilize with 100- to 150-ppm nitrogen once a week from
15-0-15 NPK liquid fertilizer, alternating with 20-10-20.
• Roots should develop in seven to nine days.

Stage 4 – Toning rooted cuttings:
• Lower air temperature to 70 to 75° F during the day and 62 to 68° F at night.
• Increase light intensity to 2,000 to 4,000 foot-candles.
• Move liners from mist area to an area of low humidity.
• Fertilize with 150- to 200-ppm nitrogen once a week from 15-0-15 alternating with 20-10-20.
• Pinch three to four weeks after sticking. Sometimes this is performed by the propagator.

GROWING ON TO FINISHED CROP

Temperature: Grandaisy likes it warmer than standard argyranthemums. Transplant and grow in the greenhouse at 60 to 65° F for two to three weeks before moving to a cooler environment. Once plants are established, begin growing at cool 44 to 55° F night temperatures. After four to six weeks of cool conditions, plants can be forced in six to eight weeks. General temperature recommendations are 65 to 79° F day temperatures and 50 to 61° F night temperatures.

Light: For Grandaisy, light intensity is more important than daylength. Recommended light levels are 6,000 to 9,000 foot-candles. Growers should plan on lighting Grandaisy to hit early spring sales windows.

Fertilizer: Constant feed of 225 to 300 ppm with a complete, water-soluble fertilizer. Keep soil pH between 5.8 to 6.2.

Plant Growth Regulators: Grandaisy is responsive to plant growth regulators. Spray 5- to 20-ppm Sumagic or drench 2- to 5-ppm Bonzi. Recommended tank mix spray rates are B-Nine at 1,500 to 2,000 ppm with Cycocel at 750 to 1,000 ppm. Apply as needed. White is more vigorous and requires more Bonzi, while Pink Halo is more compact and requires less.

In research trials, a one-time PGR application of 3-ppm Bonzi applied three weeks after transplant produced a nice round habit in a quart pot. But in general, it is recommended Grandaisy be grown in larger pots. Production trials are recommended.

Disease control: Apply a broad-spectrum fungicidal drench after planting. Watch for root rots and Botrytis.

Pest control: Monitor for thrips, aphids, whiteflies and leaf miners.

For more information about Grandaisy intergeneric argyranthemums, visit www.suntoryflowers.com.