Centaurea cyanus
The annual cornflower, Centaurea cyanus, is a cool‑season bedding and cutting flower. It stands out for clear blue blooms that also appear in pink and white forms. Plants grow best in full sun with cool spring weather. Bloom is longest where summers stay mild. In hot regions it flowers in late spring and then fades. It resows where soil is disturbed and drainage is good. Native to Europe, it is widely naturalized in North America.
At‑a‑glance
- Group/Class: Annual cornflower
- Height × spread: 12 to 24 in (30 to 60 cm) × 6 to 12 in (15 to 30 cm)
- Bloom window: late spring to early summer; longer in cool summers
- Color & flower form: mostly blue; also pink or white; tufted, fringed heads
- Fragrance: 0 none
- USDA hardiness: grown as annual in all zones
- Breeder / Year / Origin: unknown
- Cut‑flower notes: good cut flower; cut when blooms are newly open
- Pet safety: safe
How it differs
- Annual habit versus the perennial cornflowers on the pillar page
- Earlier spring bloom compared with most perennial types
- Slim, wiry stems and smaller flower heads
- Wide color range beyond blue
- Self‑seeds readily in open soil
Strengths
- Easy from direct sowing
- Handles lean, well‑drained soil
- Good drought tolerance once established
- Attractive to bees and butterflies
Care in one minute
- Choose full sun and open airflow.
- Soil: average, well‑drained; pH neutral to slightly alkaline is fine.
- Water regularly during establishment; then water when top inch is dry.
- Feeding is light; excess nitrogen causes flop.
- Pinch young plants at 6 to 8 in to branch; deadhead to extend bloom.
- In mild‑winter areas, fall‑sow; elsewhere, sow after last frost.
Watch‑outs
- Can flop in rich soil or shade
- Fades quickly as summer heat builds
- Self‑seeds; deadhead to limit spread
Best uses (tags)
cutting, borders, pollinators, meadow, cottage
Provenance note
A European arable wildflower, it has been grown in gardens for centuries and is now naturalized through much of the U.S. and southern Canada.
References
- Missouri Botanical Garden Plant Finder – Centaurea cyanus
- NC State Extension Gardener Plant Toolbox – Centaurea cyanus
- Illinois Extension – Bachelor’s Button (Centaurea cyanus)
- ASPCA – Cornflower (Centaurea cyanus) toxicity
Written by: Your Flowers Guide editorial team
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