Dahlia Summer Bees

Arnetia Verbeek-Jackson, Regional Product Manager-Specialty Annuals & Pelargonium—Dümmen Orange

New for 2026 is Dahlia Summer Bees, a pollinator’s paradise with its large, single, open flowers! Starting this new series off with two bicolors—Purple Bicolor and Red Bicolor—these charismatic and photogenic flowers make them one of the strongest impulse buys at retail. The two dahlias are upright in habit with excellent branching ... and did I mention fantastic flower power? They flower in spring and continue to flower into summer. After the first flush of flowers, there are numerous buds coming on right behind them. 

Dahlia Summer Bees are best suited for 1.25 qt. and larger in containers and are excellent in the landscape. The visually striking single bicolor flowers also make great cut flowers. The height for these pollinators is 12 to 24 in. and would need to have adequate spacing no less than 12 in. apart. While they love the sun, they also adapt well to partly shady conditions. The two bicolors can be planted together as a mixed combination in containers and they also play well with other cultivars, such as calibrachoas. Dahlia Summer Bees are a perfect solution for adding bright colorful flowers to any garden or patio that will flower all summer long! 

Propagation tips 
Dahlias thrive in nutrient rich media that’s also well-draining with sufficient moisture retention to prevent wilting. Dahlias, in general, should be kept evenly moist, avoiding dramatic wet/dry cycles that can cause more stress to the plant. A rooting hormone is not needed and recommended tray sizes can be 50 cell up to 105-cell count. The unrooted cutting should be stuck in the media up to the first set of leaves to allow stem roots to form.  

The pH range is on the lower side of 5.6 to 6.2 and the EC range is a moderate 2.0 to 3.5. Average soil temperature is 70 to 75F (21 to 23C). Dahlias are not daylength neutral and require 14-hour days, achieved through day extension during darker months. 

Be sure to scout for pests such as thrips, fungus gnats and aphids. Using yellow sticky cards in the propagation area can help identify these.
For diseases, one of the most important preventative sprays is for powdery mildew, as all dahlias are susceptible. These require a continuous spray plan starting in propagation and utilized throughout the growing cycle.  

Check for roots typically around three to four weeks to be ready for transplant.

Finishing 
When transplanting, plant deep enough to bury the first set of leaves in the soil. Some dahlias can be top-heavy—planting deep enough creates a strong foundation for the roots to develop and grow that helps stabilize the plants.  

Plants must be grown under long days with a minimum of 14 hours, but no more than 16 hours of sunlight a day. More than 16 hours daily will promote vegetative growth and delay flowering. Nighttime interruptions aren’t recommended as a substitute.

To improve branching and to increase the number of blooms, the dahlias can be pinched by removing one to two nodes two weeks after transplant. Be sure to check that the roots have been established and top growth is obvious before pinching. Pinching too early can reduce crop time and reduce the final height of the plant.  

Keep soil media moderately moist with mild dry cycles. Soil media must be well draining with a pore space of 25% to 50% to allow oxygen to reach its roots.  

A complete blend of 17-5-17 fertilizer is best for a balanced, well-shaped finished product. Dahlias are very responsive to PGRs; use the least-harsh chemical treatment to avoid stunting the plants. Some suggestions are 2,500 ppm B-Nine (85% daminozide) as a spray or 0.5ppm Bonzi (0.4% paclobutrazol).

Be sure to continue the preventative spray plan for powdery mildew. Ensure good air circulation and avoid overhead watering to reduce humidity around the plants. Paying close attention to this will help ensure a successful dahlia growing season.

Growers looking to add a new eye-catching dahlia to their program for spring and summer 2026 will appreciate how well Summer Bees aligns with current market demand and consumer preferences. With its vibrant bicolor blooms, long-season performance and pollinator appeal, it’s a standout in any lineup. GT

For more information about Dahlia Summer Bees from Dümmen Orange North America and to download our Growing Guides, visit na.dummenorange.com.