Hinomaru Cosmos is a vibrant cultivar of Cosmos bipinnatus that brings Japanese-inspired elegance to summer and fall gardens across zones 2-11. Named for Japan's national flag (hinomaru means 'circle of the sun'), this variety grows 42-48 inches tall with a compact 24-inch spread, creating an airy backdrop of finely textured foliage topped with cheerful blooms. From seed to flower takes just 63-84 days, making it remarkably fast to reach its full potential. It thrives on neglect once established, demanding little water and full sun, yet draws pollinators throughout the long blooming season from June through November.
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Full Sun
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2-11
48in H x 24in W
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High
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The speed and reliability of Hinomaru Cosmos make it a standout choice for gardeners seeking quick, dramatic results. Reaching full bloom in as little as 63 days from seed, this variety fills garden space efficiently while asking for almost nothing in return, no fertilizer, minimal water once roots establish, and zero fussiness about soil chemistry. Its extended flowering window from early summer straight through fall frost means consistent color when many other plants have faded, all while feeding bees and butterflies.
Hinomaru Cosmos excels as a cut flower for fresh arrangements, where its long stems and airy branching habit create natural, flowing compositions. In the garden, it serves as a tall backdrop planting that softens hard edges and creates height variation without blocking views. Its lightweight texture makes it useful for filling gaps between shrubs or anchoring the middle layer of mixed borders.
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Start seeds indoors in pots 4-5 weeks before your last spring frost, maintaining temperatures around 60-75°F for optimal germination. Seeds should sprout within 3-10 days under these conditions.
Transplant seedlings outdoors after the last spring frost when soil has warmed and night temperatures stay above frost range. Harden off plants by gradually exposing them to outdoor conditions over several days before planting in the garden.
Direct sow seeds in spring after the last frost date, pressing them lightly into moist soil without burying them deeply.
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