An annual plant that also answers to Cornflower, Bachelor's Button, Bluebottle, Hurtsickle, Hardheads, Knapweed, and Star Thistle. We use the genus name to keep it nice and simple.
Season & Zone
Exposure: Full sun
Direct sow starting just before last frost, and again every two weeks until end of May. Can be direct sown in autumn as well. Starting indoors is not necessary, but can be accomplished by keeping seed trays in the dark at the optimal soil temperature of 15-21°C (60-70°F). Move under bright lights once germination occurs, and transplant out in late spring, around mid-May.
Just cover the small seeds. Thin or space to 15-30cm (6-12") apart.
Any ordinary, well drained garden soil will work within the pH range of 5.5-7.0. Deadhead regularly to prolong blooming. Planting several times over the spring will produce a longer bloom time throughout summer and early fall.