Centaurea Species, Cornflower, Perennial Bachelor Button, Red Knapweed

Centaurea atropurpurea

Family: Asteraceae (ass-ter-AY-see-ee) (Info)
Genus: Centaurea (sen-TAR-ee-uh) (Info)
Species: atropurpurea (at-ro-pur-PURR-ee-uh) (Info)
Synonym:Centaurea oliveriana

Category:

Perennials

Water Requirements:

Drought-tolerant; suitable for xeriscaping

Average Water Needs; Water regularly; do not overwater

Sun Exposure:

Full Sun

Foliage:

Herbaceous

Foliage Color:

Bronze

Height:

12-18 in. (30-45 cm)

18-24 in. (45-60 cm)

24-36 in. (60-90 cm)

Spacing:

18-24 in. (45-60 cm)

24-36 in. (60-90 cm)

Hardiness:

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)

USDA Zone 9b: to -3.8 C (25 F)

USDA Zone 10a: to -1.1 C (30 F)

Where to Grow:

Grow outdoors year-round in hardiness zone

Danger:

Unknown - Tell us

Bloom Color:

Dark Purple/Black

Maroon/Burgundy

Bloom Characteristics:

Flowers are good for cutting

Flowers are good for drying and preserving

This plant is attractive to bees, butterflies and/or birds

Bloom Size:

Unknown - Tell us

Bloom Time:

Mid Summer

Late Summer/Early Fall

Other details:

May be a noxious weed or invasive

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:

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

Regional

This plant is said to grow outdoors in the following regions:

Cicero, Indiana

Gardeners' Notes:

0
positives
1
neutral
0
negatives
RatingContent
Neutral

On Jan 9, 2016, coriaceous from ROSLINDALE, MA wrote:

Deep/wine red flowers in early summer may rebloom if deadheaded. Silvery, deeply divided foliage is good throughout the season.

May reach 4' tall after several years in place. Best in lean, dry, well-drained soils. May be inclined to lodge in rich, moist soils.

Clump-forming. Hardy in Z5a-9a.

BACK TO TOP