Centaurea 'John Coutts'

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knapweed 'John Coutts'

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knapweed 'John Coutts' RHS

Synonyms

Centaurea 'John Coutts', Centaurea dealbata 'John Coutts', Centaurea hypoleuca 'John Coutts'

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Herbaceous Perennial
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A vigorous herbaceous perennial, with jagged lobed leaves white-felted beneath, and showy purplish-pink flower-heads 6cm across in summer and often into early autumn

Position

Full sun

Soil Types

Loam, Sand

Max Height

0.1-0.5 metres

Max Spread

0.1-0.5 metres

Size

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

Growing Conditions

Loam Sand
Moisture
Well–drained
pH
Alkaline or Neutral

Position

Full sun
Aspect
South–facing or West–facing
Exposure
Exposed
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)
H6

Colour & Scent

Season Stem Flower Foliage Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family
Asteraceae
Native to GB/Ireland
No
Foliage
Deciduous
Habit
Bushy
Genus
A genus of clump-forming, often woody herbaceous perennials with grey-green dissected leaves and showy pink, purple or white flowers
Name Status
Synonym

How to Grow

Cultivation

Grow in well-drained soil in full sun. Attractive to bees and butterflies

Propagation

Propagate by seed in containers in a cold frame in spring. Propagate by division in spring or autumn

Suggested planting locations and garden types

  • Coastal
  • City and courtyard gardens
  • Cottage and informal garden
  • Wildlife gardens
  • Flower borders and beds

Pruning

No pruning required

Pests

Generally pest-free

Diseases

May be susceptible to Powdery mildews