Centaurea jacea
brown knapweed
A vigorous herbaceous perennial, up to 1.5m high, with lance-shaped green leaves. Leaves and stems covered with fine white felting. Flowers in summer, producing buds encased in overlapping, light brown bracts edged with long white hairs, which open to showy mauve pink or lilac flowers, with a ring of long, narrow outer florets surrounding masses of tiny flowers in the centre
Size
Ultimate height
1–1.5 metresTime to ultimate height
2–5 yearsUltimate spread
0.5–1 metresGrowing conditions
Moisture
Well–drainedpH
Acid, Alkaline, NeutralColour & scent
| Stem | Flower | Foliage | Fruit | |
| Spring | Green Grey Silver | |||
|---|---|---|---|---|
| Summer | Pink Purple | Green Grey Silver | ||
| Autumn | Green Grey Silver | |||
| Winter |
Position
- Full sun
Aspect
South–facing or West–facing
Exposure
Exposed or ShelteredDrought resistance
Yes Hardiness
H6Botanical 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
- Europe to Siberia & Caucasus
How to grow
Cultivation
Grow in almost any well-drained soil in full sun. Thrives in poor soils but will not tolerate waterlogging
Propagation
Propagate by seed or by division, separating rhizomes in autumn
Suggested planting locations and garden types
- Coastal
- Cottage and informal garden
- Prairie planting
- Wildflower meadow
- Low Maintenance
- Flower borders and beds
Pruning
Deadhead to encourage more flowers, unless seed is required
Pests
Generally pest-free
Diseases
May be susceptible to downy mildews, powdery mildews and rust diseases
Get involved
The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.