Common Knapweed, also known as Hardheads or Black Knapweed, is one of the most hardy wildflowers found in Scotland. Its flowers can be seen all through summer and into September. Although it looks a little thistle-like, this plant has no prickles, and can be identified by its blackish spherical base of the flower head.

Its flower head is made up of lots of tiny flowers known as florets, which makes it extremely popular with butterflies and other pollinators. In the autumn, the seed head attracts a variety of seed feeding birds.

The latin name of the genus, Centaurea, is said to have come from the Greek mythological centaur Chiron, who healed his hoof with knapweed.