Blue Cornflower Button

I took this picture of this wildflower in my planter box in the backyard. Centaurea cyanus (Cornflower, Bachelor's button, Bluebottle, Boutonniere flower, Hurtsickle) is a small annual flowering plant in the family Asteraceae, native to Europe. "Cornflower" is also erroneously used for chicory, and more correctly for a few other Centaurea species; to distinguish C. cyanus from these it is sometimes called Common Cornflower. It may also be referred to as "basketflower" but this is highly misleading; the term properly refers to the Plectocephalus group of Centaurea, which is probably a distinct genus. It is an annual plant growing to 40-90 cm tall, with grey-green branched stems. The leaves are lanceolate, 1-4 cm long. The flowers are most commonly an intense blue colour, produced in flowerheads (capitula) 1.5-3 cm diameter, with a ring of a few large, spreading ray florets surrounding a central cluster of disc florets. The blue pigment is protocyanin, which in roses is red.