Conflower petals are decorative culinary flowers with a blue colour. Cornflowers come from Centaurea cyanus, a small annual flowering plant. Cornflowers are annuals that grow to 40-90 cm (16-35 inches), have 1-4 cm long lanceolate leaves and intensely blue flowerheads that are 1-3 cm (1 inch) in diameter. Weirdly the blue comes from protocyanin which also gives the red in rose blossom. The flowerhead structure in cornflowers is a ring of large spreading ray florets around a central cluster of disc florets.
Cornflower petals almost flavourless, but are a great finishing sprinkle to any cuisine. So use as a garnish in food - be it salads, rice etc wherever you feel the need for the exotic blue colour. They are also used to add colour to Earl Grey to give Imperial Earl Grey.