Psephellus Species, Cornflower, Knapweed
Centaureasimplicicaulis

Synonym:Centaurea bella

Synonym:Centaurea simplicicaulis

Category
Perennials

Water Requirements
Average Water Needs; Water regularly; do not overwater

Sun Exposure
Full Sun

Foliage
Herbaceous

Foliage Color
Bronze

Height
6-12 in. (15-30 cm)

Spacing
6-9 in. (15-22 cm)

Hardiness
USDA Zone 4b: to -31.6 °C (-25 °F)
USDA Zone 5a: to -28.8 °C (-20 °F)
USDA Zone 5b: to -26.1 °C (-15 °F)
USDA Zone 6a: to -23.3 °C (-10 °F)
USDA Zone 6b: to -20.5 °C (-5 °F)
USDA Zone 7a: to -17.7 °C (0 °F)
USDA Zone 7b: to -14.9 °C (5 °F)
USDA Zone 8a: to -12.2 °C (10 °F)
USDA Zone 8b: to -9.4 °C (15 °F)
USDA Zone 9a: to -6.6 °C (20 °F)

Where to Grow

Danger

Bloom Color
Lavender

Bloom Characteristics

Bloom Size

Bloom Time
Mid Summer

Other details

Soil pH requirements
6.1 to 6.5 (mildly acidic)
6.6 to 7.5 (neutral)
7.6 to 7.8 (mildly alkaline)

Patent Information
Non-patented

Propagation Methods
By dividing the rootball
From seed; direct sow outdoors in fall
From seed; winter sow in vented containers, coldframe or unheated greenhouse
From seed; sow indoors before last frost
From seed; direct sow after last frost
Self-sows freely; deadhead if you do not want volunteer seedlings next season

Seed Collecting
Allow seedheads to dry on plants; remove and collect seeds