Centaurea montana

RHS Plant Profile
perennial cornflower

Other common names

great blue-bottle, mountain bluet, mountain centaury

Synonyms

Cyanus montanus

Plants for pollinators
Herbaceous Perennial

A rhizomatous, mat-forming perennial about 45cm tall, with simple or lobed leaves, hairy beneath, and blue flower-heads 5cm across, reddish in the centre, from late spring to summer

Position

Full sun, Partial shade

Soil Types

Chalk, Clay, Loam, Sand

Max Height

0.1-0.5 metres

Max Spread

0.5-1 metres

Size

Time to Maturity
2–5 years
Max Spread
0.5-1 metres
Max Height
0.1-0.5 metres

Growing Conditions

Chalk Clay Loam Sand
Moisture
Moist but well–drained
pH
Acid or Alkaline or Neutral

Position

Full sun Partial shade
Aspect
South–facing or North–facing or West–facing or East–facing
Exposure
Exposed or Sheltered
Hardiness
H7

Colour & Scent

Season Stem Flower Foliage Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family
Asteraceae
Native to GB/Ireland
No
Foliage
Deciduous
Habit
Spreading branched
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
Mountains of Europe

How to Grow

Cultivation

Best grown in moist but well-drained soil in sun or partial shade, needs staking

Propagation

Propagate by seed sown in pots in a cold frame in spring or propagate by division in spring or autumn

Suggested planting locations and garden types

  • Coastal
  • Cottage and informal garden
  • Wildlife gardens
  • Cut flowers
  • Flower borders and beds
  • Ground cover

Pruning

Deadhead regularly to prolong flowering

Pests

Generally pest-free

Diseases

May be susceptible to powdery mildews