Centaurea nigra
Comon knapweed, Black knapweed, Hard heads, Lesser knapweed
- Height × spread
- 0.9m × 0.4m
- Position
- Full sun
- Hardiness
- Very cold to -20C (RHS H6)
- Flowers
- Summer
Availability
Please ask in store about availability
Many plants are seasonal. Call 01234 567890 to check current stock.
About this plant
This charming wildflower makes a foliage clump of long arching leaves. From this rises tall slender stems, up to a metre in height. At the top are the rather knobby looking flowers that give the plant its popular name - knapweed - which means knob. The flower comprises a large rounded bract covered in scales and a flat top-knot of tiny tubular florets. The long stems sway and move in the breeze. It flowers in July and is attractive to many insects so is a useful addition to the wild garden. It is happy in any well drained soil in sunny sites.
- Flower colour
- Purple
- Foliage colour
- Green
- Variegated
- No
- Scent
- No
- Shape
- Column
- Height
- 0.9m
- Spread
- 0.4m
- Season of interest
- Summer
- Flowers in
- Summer
- Evergreen
- Deciduous
- Garden style
- Wild flower meadow, Prairie garden, Cottage garden
- Sun or shade
- Likes full sun, tolerates part shade
- Soil type
- Loam (normal)
- Soil pH
- All types
- Drainage
- Well drained soil, Dry soil, Drought resistant
- Hardiness
- Very cold to -20C (RHS H6)
- Borders & containers
- Borders
- Use for
- Bee attraction, Butterfly attraction, Bird attraction
- Hazards
- No
Spring
Spring-Autumn · Outdoors
Water in dry periods
Established plants in the ground can cope with 7-10 days of dryness, and shrubs often manage 2 to 3 weeks. Water one section of the garden thoroughly each day rather than a little everywhere. Check plants in pots more often, especially in hot weather.
Summer
Summer - early · Outdoors
Feed a general fertiliser
Where plants have moderate needs for nutrients, they can simply be given a general feed, fairly early in the growth season so that the growth has plenty of time to harden off before the cold weather.
Give plants a general boost with the application of a general purpose fertiliser which is spread around the root area of the plant, with amounts as directed on the feed label.
Found in
More Centaurea
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Knapweed, Star thistle
Centaurea 'John Coutts'
John Coutts cornflower, Cornflower
Centaurea montana
Mountain knapweed, Perennial cornflower, Mountain bluet, Perennial bachelor's buttons
Centaurea 'Amethyst on Ice'
Knapweed, Star thistle
Centaurea 'Caramia'
Knapweed, Star thistle
Centaurea 'Jordy'
Knapweed
Centaurea 'Silver Feather'
Silver Feather knapweed
Centaurea bella
Beautiful knapweed