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Centaurea cyanus

Phonetic Spelling
sen-TAR-ee-ah sigh-AN-us
Description

Often seen growing as a weed in fields and along roads and railroads, Cornflower is a hardy, low maintenance cool season annual with striking blue flowers.  Cornflower is very adaptable and will tolerate poor soils and no fertilization.  It tolerates low water conditions but prefers medium moisture, well-drained soils.  Cornflower prefers full sun to light shade but the stems will flop with too much shade.  Taller plants may need staking or need to be planted with other plants that will hold them up.  Because it does better in cooler climates, seeds should be started indoors 6-8 weeks before last frost, or in mild winter climates can be seeded in situ directly outdoors in the fall.  

Plants reseed and naturalize easily so dead-heading is necessary to control the seeds.  However, if the goal is to bring birds and butterflies into the garden, limit the dead-heading. It is an attractive and long-lasting cut flower.  They have no serious insect or disease problems to note. Wilt, rots and rusts are possible. Also watch for aphids and mealybugs.

Genus came from the popular name of various plants in the late 14th century, from Medieval Latin centaurea, from Latin centaureum, from Greek kentaureion, from kentauros "centaur", so called because the plant's medicinal properties were discovered by Chiron the centaur.  Specific epithet means blue for flower color.

A blue cornflower was featured by Corning Glass Works in their initial oven-to-table ware line. It became the trademark of Corning consumer products for three decades.

See this plant in the following landscape:
Pink and White Garden
Cultivars / Varieties:
Tags:
#white#hardy#full sun tolerant#drought tolerant#wine#wildlife plants#pink flowers#showy#weedy#cut flowers#deer resistant#naturalizes#pollinator plant#early summer flowers#bird friendly#butterfly friendly#partial shade tolerant#non-toxic for horses#non-toxic for dogs#non-toxic for cats
 
Cultivars / Varieties:
Tags:
#white#hardy#full sun tolerant#drought tolerant#wine#wildlife plants#pink flowers#showy#weedy#cut flowers#deer resistant#naturalizes#pollinator plant#early summer flowers#bird friendly#butterfly friendly#partial shade tolerant#non-toxic for horses#non-toxic for dogs#non-toxic for cats
  • Attributes:
    Genus:
    Centaurea
    Species:
    cyanus
    Family:
    Asteraceae
    Life Cycle:
    Annual
    Recommended Propagation Strategy:
    Seed
    Country Or Region Of Origin:
    Western Asia, Europe
    Distribution:
    Throughout the US and southern Canada
    Wildlife Value:
    Birds and butterflies use the flowers and fruit as a food source
    Play Value:
    Easy to Grow
    Wildlife Food Source
    Particularly Resistant To (Insects/Diseases/Other Problems):
    Deer and drought tolerant
    Edibility:
    Edible
    Dimensions:
    Height: 1 ft. 0 in. - 3 ft. 0 in.
    Width: 1 ft. 0 in. - 2 ft. 0 in.
  • Whole Plant Traits:
    Plant Type:
    Annual
    Edible
    Habit/Form:
    Erect
    Growth Rate:
    Medium
    Maintenance:
    High
    Texture:
    Medium
  • Cultural Conditions:
    Light:
    Full sun (6 or more hours of direct sunlight a day)
    Partial Shade (Direct sunlight only part of the day, 2-6 hours)
    Soil Texture:
    Clay
    High Organic Matter
    Loam (Silt)
    Soil pH:
    Acid (<6.0)
    Alkaline (>8.0)
    Neutral (6.0-8.0)
    Soil Drainage:
    Good Drainage
    Moist
    Available Space To Plant:
    Less than 12 inches
    USDA Plant Hardiness Zone:
    2a, 2b, 3a, 3b, 4b, 4a, 5a, 5b, 6b, 6a, 7a, 7b, 8b, 8a, 9a, 9b, 10a, 10b, 11a, 11b
  • Fruit:
    Fruit Color:
    Cream/Tan
    Display/Harvest Time:
    Fall
    Fruit Type:
    Achene
    Fruit Length:
    < 1 inch
    Fruit Width:
    < 1 inch
    Fruit Description:
    Finely hairy, straw-colored at maturity with a tuft of short, stiff, light brown bristles at the tip.
  • Flowers:
    Flower Color:
    Blue
    Pink
    White
    Flower Inflorescence:
    Cyme
    Head
    Flower Value To Gardener:
    Edible
    Good Cut
    Showy
    Flower Bloom Time:
    Summer
    Flower Shape:
    Wheel
    Flower Petals:
    7 - 20 petals/rays
    Bracts
    Flower Size:
    1-3 inches
    Flower Description:
    An intense blue color arranged in heads approximately 1.5 inches in diameter, with a ring of a few large, spreading ray florets surrounding a central cluster of disc florets
  • Leaves:
    Leaf Color:
    Gray/Silver
    Green
    Leaf Feel:
    Smooth
    Leaf Type:
    Simple
    Leaf Arrangement:
    Alternate
    Leaf Shape:
    Lanceolate
    Pinnatifid
    Leaf Margin:
    Lobed
    Hairs Present:
    Yes
    Leaf Length:
    1-3 inches
    Leaf Width:
    < 1 inch
    Leaf Description:
    Leaves are alternate, 1 to 4 inches long, pointed at the tip that are sparsely to moderately covered in long, matted hairs, a distinguishing characteristic of this plant.
  • Stem:
    Stem Color:
    Gray/Silver
    Green
    Stem Is Aromatic:
    No
    Stem Form:
    Straight
    Stem Surface:
    Hairy (pubescent)
    Stem Description:
    Single stems from the base of the plant that then branch, are sparsely to moderately covered in woolly hairs; initially erect but tend to flop over without support of surrounding vegetation or stakes.
  • Landscape:
    Landscape Location:
    Container
    Meadow
    Naturalized Area
    Landscape Theme:
    Cottage Garden
    Cutting Garden
    Edible Garden
    Design Feature:
    Border
    Attracts:
    Butterflies
    Pollinators
    Songbirds
    Problems:
    Weedy