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Cornflower 'Black Gem'
Cornflower 'Black Gem'
Cornflower 'Black Gem'
Cornflower 'Black Gem'
Seed Packet

Cornflower 'Black Gem'

Centaurea cyanus
The cut-edged petals of cornflower Black Gem gather into small thistle-shaped flowers above silvery leaves tailor-made to showcase the dark maroon blooms. Your cottage garden will become a hive of activity as honeybees hum contentedly around the generous flowering of this long-loved hardy annual. Self-sows.
SKU #S430
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Approximate Seeds Per Packet
Annual Hardiness
Hardy Annual
Mature Size
2' h x 10" w
Full sun
Regular, well-drained
Spring to summer
Maroon cut petals and silver foliage
Great Cut Flower
Deer Resistant
Heat or Drought Tolerant
Attracts Bees
Attracts Beneficial Insects
Barely cover (about 1/16").
Sprout Time:
5-20 days
Seed To Bloom:
10 weeks
Starting Indoors:
Not recommended.
Starting Outdoors:
Sow in early spring, 3-4 weeks before last frost. Can also be fall sown (Oct.) in zones 7-10.
Cornflowers are sentimental favorites and of easiest culture; the numerous bees buzzing around the blooms are a clue to their value in pollinator gardens. A favored flower for hundreds of years in England, cornflowers had many pet names, including Bluebottle and Hurtsickle, for the cordlike stems dulled the reaper's blade. At home in the cutting, veggie, border, and meadow garden, they continue in bloom if picked often for fresh and dried bouquets. Pull some edible petals to brighten salads, and freeze inside ice cubes to add a bit of beauty to summer drinks. Try an early to mid-fall sowing in September in zones 7-10 for vigorous blooming plants earlier in the season; elsewhere, they are generally sown in early spring. Self-sows.
Final Spacing:
Water Requirements:
Medium Water Use
Watering Details:
Somewhat drought tolerant once established. 1" of water per week initially, then water during dry spells.
Soil pH:
Neutral to alkaline
Grows well in poorer soils. Mix in about 1/2" of compost or an organic granular fertilizer prior to planting.
Diseases & Pests:
Avoid fungal troubles by placing in a location that has good air circulation.
When to Cut for Bouquets:
Harvest when the flowers are just open.