The black knapweed (Centaurea nigra) is a recommended plant in perennial flower meadows, because of its long, sparse and browning flowering, its disheveled petals with a frank and certain bitterness are not without displeasing butterflies and pollinators, but will especially serve to decorate with a fiery purple. From Europe, it has come to settle wherever it is allowed to reseed, invading certain ditches, roadsides and fallow fields.