Common Knapweed
Centaurea nigra
Common Knapweed is a perennial for mid-border, suited to full sun to partial shade and clay, loam or chalk, flowering Jun, Jul, Aug, Sep.
| Type | Perennial |
|---|---|
| Mature height | 80 cm |
| Spread | 40 cm |
| Aspect | full sun to partial shade |
| Foliage | Deciduous |
| Hardiness | USDA 5a-8b, RHS H7 |
| Pollinator-friendly | Yes |
| Pet-safe | Yes |
Where to use it in a border
At around 80 cm, it sits best through the middle of a border, between taller structure behind and edging in front. Give it about 40 cm of room to spread, roughly 2 to the metre when planted in a drift. It is hardy across USDA zones 5a to 8b and rated H7 by the RHS, so check it suits your area before planting.
It appears in our lists of full sun, clay soil, chalk soil, pollinator-friendly plants, pet-safe plants.
Border Builder uses Common Knapweed's height, spread, soil, bloom months and companions to place it in a full border plan for your own conditions, on iPhone and iPad.
Flowering through the year
Worth knowing
- Its flowers are valued by bees and other pollinators.
Good companions
Plants that share its conditions and style, chosen to complement its place in the border:
- Cowslipto edge in front
- Moss Phloxto edge in front
- Ragged Robinto edge in front
- Snake's Head Fritillaryto edge in front
- Wild Daffodilto edge in front
- Bee Balm 'Jacob Cline'for height behind it