Black Gem Cornflower is a stunning heirloom variety of Centaurea cyanus that brings deep, jewel-toned blooms to spring and summer gardens. Reaching a compact 24 inches tall, this cottage garden classic flowers reliably within 70 days from seed, making it rewarding for gardeners who want quick color. It thrives in full sun with moderate water and actually improves as it matures, becoming more drought tolerant once established. Deer leave it alone, and pollinators flock to its distinctive flowers, making it both beautiful and ecologically valuable.
8
Full Sun
Moderate
2-11
24in H x 10in W
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Low
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The dark, saturated color of Black Gem sets it apart in a genus known for sky blue blooms, offering a rare depth that catches the eye in any garden. At a neat 24 inches with just 10 inches of width, it slots seamlessly into borders and containers without sprawling. Sow seed directly in early spring or even fall (in zones 7 and warmer), and you'll have blooms within 10 weeks, rewarding patient gardeners with one of the longest flowering windows of the season, stretching from March through August.
Black Gem Cornflower is primarily grown for cutting and garden display. Its long stems and distinctive dark blooms make it a natural choice for fresh flower arrangements, where it adds unexpected color depth to mixed bouquets. In the garden, it serves as a pollinator magnet and a reliable filler for cottage-style plantings and meadow gardens.
No timeline data available yet for this variety.
Sow Black Gem Cornflower seed directly outdoors in early spring, 3 to 4 weeks before your last frost date. In zones 7 through 10, you can also sow in October for fall establishment. Simply scatter seed where you want plants to grow, pressing it lightly into soil since it needs light to germinate.
Harvest Black Gem Cornflower blooms when the petals are fully unfurled and the flower face is open but still firm to the touch. Cut stems in the early morning with a sharp knife, taking as much stem length as you like since these plants produce generously throughout the season from March through August. Regular harvesting actually encourages more blooms, rewarding you for cutting.
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