Skip to site navigation

Allium caeruleum AGM

Home  |  Plants > Plant Selector > Allium caeruleum AGM

© RHS

Characteristics

Plant type

Bulb

Fragrance

Leaf

Toxicity

Resilience

Hardiness

H5 (hardy - cold winter)

Colour

Flower

Blue in Summer

Foliage

Green in Spring

Size

Ultimate height

0.5-1 metres

Ultimate spread

0-0.1 metre

Time to ultimate height

2-5 years


Preferred common name

blue-flowered garlic

Family

Alliaceae


Allium are bulbous herbaceous perennials with a strong onion or garlic scent, linear, strap-shaped or cylindrical basal leaves and star-shaped or bell-shaped flowers in an umbel on a leafless stem

A. caeruleum is a bulbous perennial up to 80cm in height, with narrow leaves often withering by flowering time. Starry blue flowers are borne in compact, rounded clusters in early summer

Other common names

  • azure-flowered garlic

Synonym(s)

  • Allium azureum
  • Allium caeruleum azureum
  • Allium coerulescens

How to grow

Sunlight

  • Full sun

Aspect

  • South-facing, North-facing, West-facing or East-facing
  • Sheltered

Cultivation

Easy to grow in fertile well-drained soil. Add grit when grown in clay soils to improve drainage

Soil

  • Well-drained or Moist but well-drained
  • Acid, Alkaline or Neutral
  • Chalk, Clay, Sand or Loam

Propagation

Propagate by seed, sowing in containers in a cold frame when just ripe or in the spring. Alternatively, remove offsets in autumn

Suggested planting locations and garden types

Cottage/Informal Garden, Flower borders and beds, Cut Flowers or Underplanting of Roses and Shrubs


How to care

Pruning

No pruning required

Pests

Generally pest free

Diseases

Generally trouble-free: Onion white rot and a downy mildew may occur