Compare with: greater knapweed

Black knapweed Centaurea nigra

Also known as: hardhead, lesser knapweed


Best time to see: mid Jul to late Sep

Key facts

A widespread perennial meadow plant with red-purple thistle-like flowers, growing up to 90 cm tall

Narrow pointed leaves grow singly up the stem; also known as hardhead because of its firm, rounded head

An important source of nectar for many species of butterfly and bee; regarded as a noxious weed in parts of North America

Extras

Plant is up to 1m tall; stems tough with long branches

Flower-head has purple narrow petals, like a shaving-brush about 2.5cm across, with a dark brown scaly part like the handle below

Leaves are dark green and pointed

  • Main photo
  • flower

Photo © Tony Gunton

Photo © Tony Gunton