Centaurea montana 'Amethyst in Snow'

RHS Plant Profile

perennial cornflower 'Amethyst in Snow'

Herbaceous Perennial

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A spreading, herbaceous perennial with grey-green foliage covered in silvery hairs. The thistle-like flowers, white with purple centres, open from scaly buds in late spring and early 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

Hardiness Ratings

All ratings refer to the UK growing conditions unless otherwise stated. Minimum temperature ranges (in degrees C) are shown in brackets

H1A: under glass all year (>15C)
H1B: can be grown outside in the summer (10 - 15)
H1C: can be grown outside in the summer (5 - 10)
H2: tolerant of low temperatures, but not surviving being frozen (1 to 5)
H3: hardy in coastal and relatively mild parts of the UK (-5 to 1)
H4: hardy through most of the UK (-10 to -5)
H5: hardy in most places throughout the UK even in severe winters (-15 to -10)
H6: hardy in all of UK and northern Europe (-20 to -15)
H7: hardy in the severest European continental climates (< -20): H7

Colour & Scent

Season	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family: Asteraceae
Native to GB/Ireland: No
Foliage: Deciduous
Habit: Matforming
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: Accepted

How to Grow

Cultivation

Best grown in moist but well-drained soil in sun or partial shade. May need staking

Propagation

Propagate by division in spring or autumn

Suggested planting locations and garden types

Coastal
Cottage and informal garden
Patio and container plants
Prairie planting
Wildlife gardens
Cut flowers
Flower borders and beds

Pruning

Deadhead regularly to prolong flowering, and cut back in autumn

Pests

Generally pest-free

Diseases

May be susceptible to powdery mildews