Common Knapweed
Scientific name: Centaurea nigra
Family: Asteraceae
Other common names; black knapweed, hard head
Flowering time: June to September
Height: 40-80cm
Growing conditions: grows well in both wetter and drier areas of the meadow
Nectar source for: Small Skipper, Essex Skipper, Silver Spotted Skipper, Brimstone, Adonis Blue, Small Tortoiseshell, Peacock, Comma, Silver-washed Fritillary, Marbled White and Meadow Brown
Food source for: seeds are eaten by birds
Description:
Black Knapweed is a tall, tough perennial flower that produces large purple thistle like flowers, often two or three to a stem. Along the Thames around Long Mead there is the rarer rayed form that we have and which is shown in the photographs. It is long flowering, providing nectar to a wide range of butterflies throughout the summer months. When the seeds are ripe the seed head opens like a goblet and the seeds fall out when brushed against by animals or rocked by the wind.
How to identify: The bright pink-purple 'flowers' of common kanpweed are actually composite flower heads made up of many small 'florets' (tiny flowers), surrounded by a crown of long, ragged, pink bracts (leaf-like structures). It has deeply divided, oblong leaves.
How to propagate: Propagate by seed or division.
Family: Asteraceae
Other common names; black knapweed, hard head
Flowering time: June to September
Height: 40-80cm
Growing conditions: grows well in both wetter and drier areas of the meadow
Nectar source for: Small Skipper, Essex Skipper, Silver Spotted Skipper, Brimstone, Adonis Blue, Small Tortoiseshell, Peacock, Comma, Silver-washed Fritillary, Marbled White and Meadow Brown
Food source for: seeds are eaten by birds
Description:
Black Knapweed is a tall, tough perennial flower that produces large purple thistle like flowers, often two or three to a stem. Along the Thames around Long Mead there is the rarer rayed form that we have and which is shown in the photographs. It is long flowering, providing nectar to a wide range of butterflies throughout the summer months. When the seeds are ripe the seed head opens like a goblet and the seeds fall out when brushed against by animals or rocked by the wind.
How to identify: The bright pink-purple 'flowers' of common kanpweed are actually composite flower heads made up of many small 'florets' (tiny flowers), surrounded by a crown of long, ragged, pink bracts (leaf-like structures). It has deeply divided, oblong leaves.
How to propagate: Propagate by seed or division.