About
Centaurea cyanus 'Blue Boy' is an annual cornflower that reaches a height of approximately 80 cm when in bloom. It features lance-shaped, grey-green foliage. Throughout the summer, it produces prominent flower heads measuring 3-4 cm in diameter, showcasing bright blue florets arranged around a center of dark purple stamens.
About the genus
Centaurea includes annuals, perennials, and subshrubs, characterized by simple or pinnately lobed foliage and prominent flower heads resembling thistles, frequently featuring enlarged outer florets.
Growing conditions
- Sunlight
- Full sun
- Soil type
- Chalk, Loam, Sand
- Soil pH
- Acid, Alkaline, Neutral
- Soil moisture
- Well-drained
- Aspect
- South-facing, West-facing
- Exposure
- Exposed, Sheltered
- UK hardiness
- H6
Plant details
- Plant type
- Annual Biennial
- Habit
- Clump forming
- Foliage
- Deciduous
- Height
- 0.5-1 metres
- Spread
- 0.1-0.5 metres
- Time to full height
- 1 year
- Suggested uses
- Coastal, Cottage and informal garden, Wildflower meadow, Wildlife gardens
Care notes
- Cultivation
- Grow in almost any well-drained soil in full sun. Thrives in poor soils but will not tolerate waterlogging
- Pruning
- Deadhead to encourage more flowers, unless seed is required
- Propagation
- Propagate by seed (sown outdoors) in early spring. Sow successionally rather than all at once for a longer show of flowers
- Pest resistance
- Generally pest-free
- Disease resistance
- May be susceptible to downy mildews, powdery mildews and rust diseases