Rhaponticum centaureoides

RHS Plant Profile

great thistle

Synonyms

Centaurea 'Pulchra Major'
Stemmacantha centaureoides
Leuzea centaureoides
Cnicus centauroides
Centaurea cynaroides Link
Stemmacantha cynaroides Cass.

Herbaceous Perennial

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A clump-forming perennial to around 1.2m high, with narrowly ovate, lobed and toothed green leaves up to 45cm long, with silvery undersides. Stiff, upright stems bear rounded, scaly buds that open to thistle-like flowers with masses of fine purple-pink florets in midsummer

Position

Full sun

Soil Types

Chalk, Loam, Sand

Max Height

1-1.5 metres

Max Spread

0.5-1 metres

Size

Time to Maturity: 2–5 years
Max Spread: 0.5-1 metres
Max Height: 1-1.5 metres

Growing Conditions

Chalk Loam Sand

Moisture: Moist but well–drained or Well–drained
pH: Acid or Alkaline or Neutral

Position

Full sun

Aspect: South–facing or West–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): H5

Colour & Scent

Season	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family: Asteraceae
Native to GB/Ireland: No
Foliage: Deciduous
Habit: Clump forming, Columnar upright
Genus: A genus of flowering perennials, native to Siberian alpine meadows with green foliage and pink, thistle-like flowerheads
Name Status: Correct
Plant Range: Pyrenees (France, Spain)

How to Grow

Cultivation

Grow in moderately fertile, moist but well-drained soil in full sun

Propagation

Propagate by seed or by division in spring

Suggested planting locations and garden types

Cottage and informal garden
Gravel garden
Flower borders and beds

Pruning

Can be cut back after flowering, or left to provide winter interest

Pests

Generally pest-free

Diseases

Generally disease-free