Rosetta Cosmos is a summer-to-fall bloomer that brings reliable color to gardens from June through November, reaching a compact 30 to 36 inches tall. This cultivar of Cosmos bipinnatus thrives in full sun with minimal water once established, making it drought tolerant and low-maintenance. Seeds germinate quickly, flowering within 56 to 84 days from sowing, so you'll see blooms relatively fast. Its pollinator-attracting flowers and ability to handle dry spells make it a dependable choice for sunny borders and beds.
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Full Sun
Low
2-11
36in H x 18in W
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Rosetta Cosmos seeds germinate in just 3 to 10 days and reach bloom in roughly 2 to 3 months, giving you flowers from early summer straight through the first frost. Once established, it needs almost no watering beyond occasional deep soaks during heat waves, freeing you from daily garden chores. The plant's compact height of 30 to 36 inches and controlled spread make it work in tight spaces or mixed plantings without overwhelming neighbors.
Rosetta Cosmos is grown for its ornamental flowers in summer and fall gardens. The blooms attract pollinators like bees and butterflies, making it valuable for supporting local pollinator populations. In mixed borders, cutting gardens, and pollinator-focused plantings, this variety provides sustained color and insect activity over months.
No timeline data available yet for this variety.
Start seeds indoors in pots 4 to 5 weeks before your last spring frost. Keep soil and air temperature around 60 to 75 degrees Fahrenheit. Transplant outdoors after the last frost date when seedlings are sturdy.
Move seedlings outdoors after the last spring frost, when nighttime temperatures reliably stay above 50 degrees. Space plants 18 inches apart to allow room for mature spread.
Direct sow seeds outdoors in spring after the last frost date. Press seeds into prepared soil and keep moisture consistent until germination.
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