Flower of an Hour (Hibiscus trionum) is a charming annual that lives up to its poetic name, producing delicate, showy blooms that open in morning sun and close by afternoon. Native to tropical and temperate Eurasia, this easy-to-grow plant reaches 18-24 inches tall with multiple branching stems clothed in deeply lobed, dark green leaves. It thrives in full sun across hardiness zones 2-11, blooming generously from June through frost with minimal fuss. The plant's aggressive self-seeding habit means it will cheerfully return year after year once established, making it a low-maintenance way to add continuous color to gardens, borders, or containers.
Full Sun
Moderate
2-11
24in H x 24in W
—
Low
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Delicate cup-shaped flowers that open fresh each morning and fade by evening give this plant its distinctive common name, creating an ephemeral quality that draws the eye back daily. The plant's ability to thrive in poor soils and challenging sites where other annuals struggle, combined with its complete lack of serious insect or disease problems, makes it nearly impossible to kill. Deer leave it untouched, and once established, its prolific self-seeding means you'll have fresh plants year after year without replanting.
Flower of an Hour serves primarily as an ornamental annual, valued for adding seasonal interest to flower gardens, borders, and containers. Its compact size and prolific blooming habit make it useful for filling gaps in beds or creating naturalized drifts in informal landscapes. The plant's tolerance for poor, disturbed soils means it excels in challenging garden spots where conventional annuals struggle.
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Transplant hardened-off seedlings outdoors after the last frost date once soil has warmed. Space plants 18-24 inches apart to accommodate their mature spread.
Direct sow seeds outdoors after the last spring frost into prepared garden beds or containers. The plant self-seeds so reliably that once you've grown it once, volunteer seedlings often handle future seasons without your intervention.
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“Hibiscus trionum's exact origins remain somewhat mysterious, though it's believed native to tropical and temperate Eurasia. Over centuries, it escaped cultivation and naturalized throughout much of the world, finding its way along roadsides, railroad tracks, and open fields, spreading wherever bare earth offered opportunity. This journey from garden escapee to global wanderer speaks to the plant's determination and adaptability, a testament to how a single species can thrive across continents through the simple act of producing abundant seed.”