Sensation Cosmos is an award-winning open-pollinated variety that transforms the garden with abundant, cheerful blooms from late July through September. This compact cosmos reaches its peak flowering in mid to late August, producing flowers so excellent for cutting that they've earned recognition from seed professionals. Growing 9 inches apart in full sun, plants mature in 75 to 90 days and thrive across hardiness zones 2 through 11, making them accessible to nearly every gardener. The real appeal lies in their reliability: sown after the last frost or started indoors 5 to 7 weeks prior, they deliver consistent color all summer long with just a bit of deadheading to keep the flowers coming.
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2-11
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Sensation Cosmos earns its reputation as an award-winning favorite through prolific, long-season blooming that peaks in late summer. The compact growth habit means you can tuck these plants into tight spaces while still harvesting armfuls of fresh-cut flowers. Morning-harvested blooms with petals just opening last remarkably well in the vase, especially when a few drops of bleach are added to the water. Deadheading is the secret to nonstop color all summer, and pinching young plants encourages fuller branching for even more flowers.
Sensation Cosmos excels as a cut flower. Harvest blooms in the morning when petals are just opening but not yet flattened for the longest vase life. A clean knife dipped in a 10 percent household bleach solution keeps stems healthy, and a few drops of bleach in the vase water will significantly extend the beauty of your arrangements.
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Sow seeds indoors in 50-cell plug flats or your preferred seedling containers 5 to 7 weeks before your last frost date. Cover seeds lightly with soil, maintaining a germination temperature between 65 and 80 degrees Fahrenheit. Seeds will typically sprout within 6 to 15 days. Once seedlings develop their first true leaves, harden them off gradually by exposing them to outdoor conditions over several days before transplanting.
Transplant seedlings outdoors after all danger of frost has passed. Space plants 9 inches apart in a location with full sun exposure. Water gently after planting to settle the soil around roots.
Direct sow seeds after your last frost date, once soil temperature reaches at least 60 degrees Fahrenheit. Cover seeds lightly with soil. For stronger plants, pinch back young seedlings once they've developed several sets of leaves to encourage branching.
Harvest blooms in the morning when they are at their freshest and petals are just opening but not yet flattened. Use a clean knife that has been dipped in a 10 percent household bleach solution to cut stems. Blooms harvested at this stage will have the longest vase life.
Pinching young plants encourages branching and fuller growth, resulting in more stems and flowers. Regular deadheading throughout the season is essential to maintain continuous blooms; remove spent flowers before they set seed.
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