Photo of Centaurea cyanus 'Blue Diadem' flower by Annie's Annuals & Perennials

Photo by Annie's Annuals & Perennials

Used with permission, all rights reserved

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Centaurea cyanus 'Blue Diadem'

Also Known As

  • Cyanus segetum 'Blue Diadem'
  • Blue Diadem Bachelor's Buttons

Plant type

annual / biennial

size

  • H: 24"-36"
  • W: 12"-30"

planting zones

  • 1-11

More Options

Centaurea cyanus 'Blue Diadem' plant details

Centaurea cyanus 'Blue Diadem' is a broadleaf deciduous annual / biennial with green foliage. In spring and summer blue flowers emerge. Attracts bees and butterflies making it an excellent addition to pollinator gardens. Grows well with sun - mostly sun and occasional - low water. Drought tolerant once established. Prefers to be dry in summer. Does well in lean and well-drained soil. A good option if you're seeking something heat tolerant.

CHARACTERISTICS OF Centaurea cyanus 'Blue Diadem'

Plant type: annual / biennial
Plant family: asteraceae
Foliage: deciduous green
Mature size: 12 IN - 30 IN - wide, 24 IN - 36 IN - tall
Flowers: blue blooms in spring and summer
Uses: cottage garden, cutting garden, easy-to-grow, self-sowing

GROWING CONDITIONS for Centaurea cyanus 'Blue Diadem'

USDA Zones: 1 - 11
Sun exposure: sun - mostly sun
Watering frequency: occasional - low
Resistant to: heat
Soil needs: lean and well-drained

Nursery contributed plant descriptions

True blue as can be, these double flowers with violet centers are covered with busy bees all summer. Cheerful blooms all season long in moderate summer areas, no fussing over needed! Easy to grow and wonderful cut.
How hard is it to find old-fashioned TALL “Bachelor Buttons” these days? Unless you grow them from seed, you’ll probably only find those squatty ones sprayed with dwarfing chemicals that will never look as charming as these! Bright, richest blue, 2.5” wide, edible blooms on upright 3’ branched stems is what you want and our favorite, ‘Blue Diadem,’ truly delivers! Perfect mid-bed, it makes the sweetest cut flowers. Rich soil is best, kiddies. To 1’ wide. Dead-head to prolong flowering, & you’ll have blooms Spring & Summer. Self-sows – woo-hoo!

By: Annie's Annuals & Perennials

Gardening facts about Centaurea cyanus 'Blue Diadem' plant

How to Grow Centaurea cyanus 'Blue Diadem'

  • Sun Exposure

    • sun - mostly sun
  • Water Needs

    • occasional - drought tolerant
  • Water Needs

    • dry in summer
  • Soil Needs

    • lean
    • well-drained
  • Special Situation

    • heat tolerant

Features

  • Foliage Color

    • green
  • Flower Color

    • blue
  • Wildlife

    • bees
    • butterflies
  • Flower Season

    • spring
    • summer
  • Foliage Season

    • deciduous

See other plant types of Centaurea for your garden

aka Cornflower

Plant Type

Perennial

Zones

6a-10b

Size

Height: 24"

Width: 12"

  • sun
  • occasional - drought tolerant
Photo of Centaurea orientalis flower by Dancing Oaks Nursery
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aka Cyanus segetum 'Black Gem', Black Gem Bachelor's Buttons

Plant Type

Annual / Biennial

Zones

1-11

Size

Height: 12"-24"

Width: 6"-12"

  • sun
  • regular - drought tolerant
  • dry in summer
Photo of Centaurea cyanus 'Black Gem' flower, form by Annie's Annuals & Perennials
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aka Centaurea scabiosa 'Perennial Butterfly', Greater Knapweed, Perennial Bachelor Button, Perennial Butterfly Cornflower

Plant Type

Perennial

Zones

3a-10b

Size

Height: 2'

Width: 3'

  • sun - mostly sun
  • regular - occasional
Photo of Centaurea scabiosa flower by Annie's Annuals & Perennials
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aka Centaurea candidissima, Centaurea gymnocarpa, Dusty Miller, Velvet Centaurea, Velvet Centaurea

Plant Type

Shrub, Perennial

Zones

7a-10b

Size

Height: 3'-4'

Width: 8'

  • sun - mostly sun
  • regular - drought tolerant
  • dry in summer
Photo of Centaurea cineraria flower, foliage by Annie's Annuals & Perennials
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aka Centaurea uniflora ssp. nervosa, Singleflower Knapweed

Plant Type

Perennial

Zones

7a-10b

Size

Height: 20"-24"

Width: 12"-18"

  • sun
  • regular
Photo of Centaurea nervosa flower, foliage by Far Reaches Farm
View Plant

More Options

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