Centaurea cyanus

RHS Plant Profile
cornflower

Other common names

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

Synonyms

Centaurea pulchra

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