Centaurea cyanus

RHS Plant Profile
cornflower

Other common names

barbeau, blaver, blue blaw, blue bonnets, blue bow, blue sailors, blue tops, break-your-spectacles, brushes, bunk, corn binks, corn centaury, cornbottle, French pink, happy skies, haw dods, hurtsickle, ragged sailor, bachelor's buttons, blawort, blue poppy, bluebottle, bluets, ragged robin, witches' bells, penlas yr ŷd

Plants for pollinators
Annual Biennial

A cornflower annual to 75cm tall, with lance-shaped, slightly lobed, mid-green leaves, and solitary deep blue flowerheads 3-4cm across, with violet-blue inner florets, in late spring and summer

Position

Full sun

Soil Types

Loam, Sand

Max Height

0.5-1 metres

Max Spread

0.1-0.5 metres

Size

Time to Maturity
1–2 years
Max Spread
0.1-0.5 metres
Max Height
0.5-1 metres

Growing Conditions

Loam Sand
Moisture
Well–drained
pH
Acid or Alkaline or Neutral

Position

Full sun
Aspect
South–facing or West–facing
Exposure
Exposed or Sheltered
Hardiness
H6

Colour & Scent

Season Stem Flower Foliage Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family
Asteraceae
Native to GB/Ireland
Yes
Foliage
Deciduous
Habit
Clump forming
Genus
Centaurea may be annuals, perennials or subshrubs, with simple or pinnately lobed leaves and showy thistle-like flowers-heads, often with enlarged outer florets
Name Status
Correct
Plant Range
N Temperate regions

How to Grow

Cultivation

Grow in well-drained soil in full sun

Propagation

Propagate by seed sown in-situ in spring or autumn

Suggested planting locations and garden types

  • Coastal
  • Cottage and informal garden
  • Patio and container plants
  • Wildflower meadow
  • Wildlife gardens
  • Cut flowers
  • Flower borders and beds

Pruning

Deadhead regularly to prolong flowering

Pests

Generally pest-free

Diseases

May be susceptible to Powdery mildews