Alphabetical Plant Listing

Allium caeruleum (Ornamental Onion)

Allium Caeruleum, Allium azureum, Allium caeruleum azureum, Allium Coerulescens, Azure-Flowered Garlic, Blue-Flowered Garlic, Flowering Onion, Ornamental Onion, Spring Bulbs, Spring Flowers


Award-winner Allium caeruleum is a stunning ornamental onion with its inflorescence consisting of dozens of small star-shaped bright blue flowers forming a 1-inch wide (3 cm) globe-shaped cluster atop stiff stems and narrow green leaves. Prized for its true blue color, Allium caeruleum provides interesting ornamental value in the garden in late spring to early summer.

  • Growing up to 12-24 in. tall (30-60 cm), Allium caeruleum forms dense, slowly-spreading clumps over time. It naturalizes easily and will come back year after year! Since the leaves wither before the flowers emerge, plant your Allium caeruleum with other mid-sized plants to hide the faded foliage.
  • Awarded the prestigious Award of Garden Merit by the Royal Horticultural Society
  • Easily grown in richsandy to grittydry to medium moisturewell-drained soils in full sunDrought tolerant.
  • Attracts butterflies, but deer ignore it! 
  • Stunning in bedsborders, cottage gardens. Spectacular in large sweeping drifts. For best visual impact, plant in groups (at least 10 to 15 bulbs). Excellent as cut flowers for both fresh and dried arrangements!
  • Mixes beautifully with other late spring flowering bulbs and creates stunning combinations with pink or white Delphiniums, Peonies or Irises.
  • To be planted in fall.

Many hundreds of Allium species exist, but only a modest few have made a name for themselves as garden plants. The ornamental onions distinguish themselves by their great diversity in color, inflorescence and flowering height. Many species bloom in early summer - just after the spring-flowering period and just before the exuberant full bloom of summer. All species can be used in the border. Certain small species are just perfect for a rock garden, and several lend themselves to naturalizing.

Learn How To Plant And Care for Your Spring Flower Bulbs

 To achieve optimum flowering results, it is important to plant the bulbs at the right time.

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Requirements

Hardiness 4 – 10
Heat Zones 1 – 10
Climate Zones 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24
Plant Type Bulbs
Plant Family Alliums
Exposure Full Sun
Season of Interest Spring (Late)
Summer (Early)
Height 1' – 2' (30cm – 60cm)
Spread 6" – 1' (15cm – 30cm)
Spacing 2" (5cm)
Depth 4" (10cm)
Water Needs Average
Maintenance Low
Soil Type Chalk, Clay, Loam, Sand
Soil pH Acid, Alkaline, Neutral
Soil Drainage Moist but Well-Drained, Well-Drained
Characteristics Cut Flowers, Fragrant, Plant of Merit, Showy
Tolerance Deer, Drought, Rabbit
Attracts Butterflies
Garden Uses Beds and Borders, Underplanting Roses and Shrubs
Garden Styles Informal and Cottage

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Great Plant Combination Ideas with Alliums

Guides with Alliums


ikrolevetc / 123RF Stock Photo

While every effort has been made to describe these plants accurately, please keep in mind that height, bloom time, and color may differ in various climates. The description of these plants has been written based on numerous outside resources.


Requirements

Hardiness 4 – 10
Heat Zones 1 – 10
Climate Zones 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24
Plant Type Bulbs
Plant Family Alliums
Exposure Full Sun
Season of Interest Spring (Late)
Summer (Early)
Height 1' – 2' (30cm – 60cm)
Spread 6" – 1' (15cm – 30cm)
Spacing 2" (5cm)
Depth 4" (10cm)
Water Needs Average
Maintenance Low
Soil Type Chalk, Clay, Loam, Sand
Soil pH Acid, Alkaline, Neutral
Soil Drainage Moist but Well-Drained, Well-Drained
Characteristics Cut Flowers, Fragrant, Plant of Merit, Showy
Tolerance Deer, Drought, Rabbit
Attracts Butterflies
Garden Uses Beds and Borders, Underplanting Roses and Shrubs
Garden Styles Informal and Cottage

Great Plant Combination Ideas with Alliums

Guides with Alliums

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