Centaurea macrocephala
giant knapweed
A large, clump-forming perennial with simple or lobed leaves and yellow flower-heads 5cm across opening in summer from brown buds
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Size
Ultimate height
1–1.5 metresTime to ultimate height
2–5 yearsUltimate spread
0.1–0.5 metresGrowing conditions
Moisture
Moist but well–drainedpH
Acid, Alkaline, NeutralColour & scent
Stem | Flower | Foliage | Fruit | |
Spring | Green | |||
---|---|---|---|---|
Summer | Yellow | Green | ||
Autumn | Green | |||
Winter |
Position
- Full sun
- Partial shade
Aspect
West–facing or South–facing or North–facing or East–facing
Exposure
Exposed or Sheltered Hardiness
H7Botanical details
- Family
- Asteraceae
- Native to the UK
- No
- 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
- Caucasus
How to grow
Cultivation
Best grown in moist but well-drained soil in sun or partial shade
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
- Wildflower meadow
- Wildlife gardens
- Cut flowers
- Flower borders and beds
Pruning
Deadhead regularly to prolong flowering
Pests
Generally pest-free
Diseases
May be affected by powdery mildews
Get involved
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