Also known as black knapweed, this sometimes hairy perennial is a firm favourite with the insects. The brush-like flower heads are made up of reddish purple florets with a swollen base covered in brown bracts. Flowering from June until September, this plant prefers grasslands and meadows, often covering large areas. Sowing rate: 1-2g per m2 Recommended sowing times: March-May, August-October RHS plants for pollinators