Sunbeckia rudbeckia

Culture Report: Rudbeckia Sunbeckia Series By Kathy McKay

Make a statement — flowers the size of your hand and no pinching required!

Rudbeckia hirta is a key item in many growers’ summer and fall programs in North America. With its cheerful yellow blooms, the plants brighten consumer landscapes and patios. With the addition of the Sunbeckia series, consumers and growers alike will be amazed by the size of the flower and the ease in growing the plant.

Easily recognizable for its large and long-lasting blooms, this series is quickly proving to be a standout. This new collection currently has 13 varieties and is well-branching with strong, sturdy stems. Sunbeckia requires no pinching and flowers spring through fall. Plant height is approximately 14 to 16 inches. Sunbeckia is hardy to Zones 7 through 10.


The Sunbeckia series was commercially introduced in North America in 2021. It was bred in Germany by Hartwig Bull of Bull Breeding. Hartwig has been in the horticulture industry his entire life, as his parents owned a greenhouse business. In time, he and his wife Ulrike took over the family business. They have further developed the breeding business his father started in annuals and perennials.

Because of this family history, Hartwig breeds from a “grower point of view.” Hartwig and his team focus their breeding efforts on season-extending crops — plants that are innovative but also have amazing shelf life, eye-catching appeal, and are easy to grow. The goal was and continues to be to leave the field of mainstream production and find niche markets. Main crops of focus are Rudbeckia hirta, perennial helianthus and echinacea.


The rooting and finishing of rudbeckia Sunbeckia is quick and straightforward. Sunbeckia is produced via tissue culture. The tissue culture should be stuck as soon as possible after arrival.

It is recommended to grow the liners in a 72 cell or similar size. After sticking the tissue culture, immediately place it in an area with high humidity and consistent day/night temperature of 68 to 72° F for the first seven to 10 days or until roots are clearly visible. Total rooting time will be approximately five to six weeks after sticking.


Sunbeckia is suitable for many pot sizes including 6 inch, gallon, 8 inch and larger. It is suggested to allow eight to 10 weeks after transplant to finish for 6-inch and gallon containers. For 8-inch containers, the timing is 10 to 11 weeks after transplant.


Remove liners carefully from trays so as to not damage roots. Plant liner even with soil line when transplanting. Keep the soil surface of liner level with the surface of the finished pot.


Recommended temperature is 60 to 64° F days and 50 to 55° F nights. Vernalization is not required for flowering. Long days (12+ hours) are required for flowering of Sunbeckia.


Use a well-drained soil mix with a pH range of 5.5 to 6.0. Soil moisture should contain coarse components for good drainage. Proper watering and allowing soil to dry between irrigation is important. Avoid overwatering especially during cool, cloudy weather.


Sunbeckia should be grown using a well-balanced fertilizer (15-15-15 or similar) about once a week. Calcium nitrate can help with growth if plants are too small. An application of 175- to 225 ppm nitrogen is recommended. Applying an occasional clear water irrigation is recommended for maximum growth and root quality.


PGRs can be applied when the bottom shoots start to stretch, as well as later, when the flower buds are visible and stems start to stretch. B-Nine is beneficial and can be applied approximately three to four weeks after transplant. If needed, Bonzi in the later weeks can be applied.


Watch for mites, thrips and aphids, Botrytis, Pythium and Phytophthora.

The Rudbeckia hirta Sunbeckia series is available exclusively from Flamingo Holland.

Kathy McKay

Kathy McKay is director of product development with Flamingo Holland and can be reached at or 360.202.5333.

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