Scientific: Centaurea cyanus
Common: bachelor buttons, blue bachelor buttons, corn flower
Family: Asteraceae
Origin: South England, Whales, northwestern Europe and the Mediterranean region of southern Europe, but has naturalized across nearly all of the continental United States and Canada.

Pronounciation: Cen-TUR-e-a sigh-AN-us

Hardiness zones
Sunset
All (warm or cool season annual depending on zone)
USDA All (warm or cool season annual depending on zone)

Landscape Use: Accent plant for flower borders

Form & Character: Upright, open, cool, informal, free spirited.

Growth Habit: Rapidly growing herbaceous annual branching to 2 to 3 feet in height.

Foliage/Texture: Leaves are covered with small white hairs causing the plant to have a blue-gray appearance, older leaves are lyrate-pinntified or narrowly oblanceolate, entire or broadly serrate, young leaves a linear to linear lanceolate, highly pubescent, sessile; medium texture.

Flowers & Fruits: Multiple ray flowers to 1 inch in diameter.

Seasonal Color: Plants bloom heavily during the cool season in Phoenix. Many flower colors are available such as pink, light blue, medium blue, blue-violet, white, and off white.

Temperature: Avoid high heat of western exposures.

Light: Full sun to partial shade.

Soil: Tolerant, but in Phoenix does best in organic amended soil that is well drained.

Watering: Regular supplemental water is necessary in Phoenix.

Pruning: Remove spent flowers.

Propagation: Seed; fresh seed germinate quickly in 7 to 25 days at 60o to 70oF with no additional treatment.

Disease and pests: None

Additional comments: Grows quickly and blooms heavily. This is a surprisingly easy plant to culture in flower borders in Phoenix as a fall, winter or spring annual. It's not for summer though (way too hot). Many named cultivars including:

'Blue Boy' - grows to more than two feet. 'Polka Dot Mix' comes with flowers of many colors.
'Dwarf Midget' - produces bushy plants that grow only to 1 foot height.
'Black Magic' - produces dark maroon flowers.
'Sweet Sultan Imperalis' produces long-stalked flowers that are perfect for cutting.

Bachelor buttons is an outstanding performer for mixed flower borders whether your preference is for cutting or admiring. It is attractive to bees, butterflies and/or birds. The nickname "cornflower" comes from the fact that the plant grows wild in the grain fields of southern Europe. It has naturalized throughout much of North America.