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Bachelor's Button, Cornflower
Centaurea cyanus 'Blue Diadem'

Family: Asteraceae (ass-ter-AY-see-ee) (Info)
Genus: Centaurea (sen-TAR-ee-uh) (Info)
Species: cyanus (SY-an-us) (Info)
Cultivar: Blue Diadem

Category:

Annuals

Height:

24-36 in. (60-90 cm)

Spacing:

6-9 in. (15-22 cm)

Hardiness:

Not Applicable

Sun Exposure:

Full Sun

Danger:

N/A

Bloom Color:

Medium Blue

Bloom Time:

Late Spring/Early Summer

Mid Summer

Late Summer/Early Fall

Foliage:

Herbaceous

Silver/Gray

Blue-Green

Velvet/Fuzzy-Textured

Other details:

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

Average Water Needs; Water regularly; do not overwater

Self-sows freely; deadhead if you do not want volunteer seedlings next season

Flowers are good for drying and preserving

Soil pH requirements:

7.6 to 7.8 (mildly alkaline)

7.9 to 8.5 (alkaline)

Patent Information:

Unknown - Tell us

Propagation Methods:

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

Seed Collecting:

Collect seedhead/pod when flowers fade; allow to dry

Allow seedheads to dry on plants; remove and collect seeds

Properly cleaned, seed can be successfully stored

Regional

This plant has been said to grow in the following regions:

Redwood City, California

Richmond, California

San Jose, California

Charleston, West Virginia

Madison, Wisconsin

Gardeners' Notes:

2
positives
0
neutrals
0
negatives
RatingContent
Positive

On Sep 26, 2007, rebecca101 from Madison, WI (Zone 5a) wrote:

This was a very fine bachelor's button, although overall I'd say not worth the extra $$ I shelled out for it as compared to the cheap standard varieties. The flowers on Blue Diadem are a bit more refined looking - they're flatter and somewhat larger. A lovely shade of blue. I didn't find them to be as large as advertised though (the source I bought them from claimed they get to be 4" across - mine were nowhere near that.)

Positive

On Jan 16, 2005, LilyLover_UT from Ogden, UT (Zone 5b) wrote:

This tall cornflower has striking, bright blue, double flowers and silvery-green foliage. 'Blue Diadem' has larger flowers than most varieties. Cornflowers attract a wide range of beneficial insects.