Common Knapweed (Centaurea nigra) is sometimes known as Lesser Knapweed or Black Knapweed and is a member of the Daisy Family.
This plant can grow up to a meter high with leaves that are around 25 cm in length, usually deeply lobed and hairy, the lower leaves are stalked while the upper leaves are stalkless.
The flower itself is made up of black / brown bristly phyllaries. The head of each plant then produces from the bristly phyllaries, a bright purple coloured petal. The flower heads are thistle like but the stem and leaves are all spineless. The flowers are in bloom from June to September and produce the bright purple colour, but on occassions the flower has also been known to produce a white colour. Beneath the flower there is the overlapping, hard bracts which appear slightly swollen at the top end of the stem, and are a light brown colour.
Common Knapweed is absent from very damp or acid sites, it can persist for many years in a range of environments, from grazed pastures and neglected grassland to waste grounds and woodland edges. However, for this plant to regenerate it has to allow the seeds to establish in the ground. The flowers are pollinated by insects such as Bees, Flies, Butterflies and Beetles, as a result of all this insect activity attracts seed feeding birds for example the Goldfinch.
Height: 30 – 60cm
Flowering Time: June – Sept
Preferred Conditions: Thrives in the sun and well drained soil.