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Allium caeruleum (A. azureum)

Common Name(s):

Previously known as:

  • Allium azureum
Phonetic Spelling
AL-ee-um seh-ROO-lee-um
This plant has low severity poison characteristics.
See below
Description

Ornamental Onion is a bulb native to Asia with clear blue flowers in 1-inch clusters above 20- 24 inch naked stems in May-June. The leaves clasp the lower stem but often disappear by blooming time. They spread by bulblets and self-seeding. Plant bulbs 6 inches deep in the fall for spring blooms. They tolerate summer drought but require moisture during the growing season. Deer, rabbits and voles tend to avoid the plants. They can be weedy in the garden and disturbed areas so deadhead to prevent self-seeding.

Plant in humus-rich well-drained moist to dry loams in full sun for best blooming. Use in perennial beds, rock gardens, meadows, cottage garden, and naturalized areas. Also good as a cut flower.

VIDEO Created by Elisabeth Meyer for "Edibles, Bulbs, and Houseplants" a plant identification course offered in partnership with Longwood Gardens.   

More information on Allium.

Profile Video:
See this plant in the following landscape:
Cultivars / Varieties:
  • 'Blue Drumstick'
    Darker blue flower
  • ‘Heacock Form’
    Larger blue inflorescence
'Blue Drumstick', ‘Heacock Form’
Tags:
#bulb#full sun#blue#perennial#blue flowers#cut flowers#spring flowers#cottage garden#groundcover#rock gardens
 
Cultivars / Varieties:
  • 'Blue Drumstick'
    Darker blue flower
  • ‘Heacock Form’
    Larger blue inflorescence
'Blue Drumstick', ‘Heacock Form’
Tags:
#bulb#full sun#blue#perennial#blue flowers#cut flowers#spring flowers#cottage garden#groundcover#rock gardens
  • Attributes:
    Genus:
    Allium
    Species:
    caeruleum
    Family:
    Alliaceae
    Life Cycle:
    Bulb
    Perennial
    Recommended Propagation Strategy:
    Division
    Country Or Region Of Origin:
    Central Asia
    Particularly Resistant To (Insects/Diseases/Other Problems):
    Drought, normally not susceptible to animals
    Edibility:
    Flowers have a mildly bitter flavor and like young leaves can be eaten in small quantities raw in salads and sandwiches or cooked in tea and soups. However, the plant also has poisonous characteristics as noted in the "Poisonous to Humans" section of this record. Toxicity can depend on the age of the person or animal, the age of the plant, the part of the plant ingested, how much is ingested, whether the person or animal has sensitivities or allergies, whether it's eaten raw or cooked, and so forth. Consult with a medical professional for further details.
    Dimensions:
    Height: 1 ft. 0 in. - 2 ft. 0 in.
    Width: 0 ft. 6 in. - 1 ft. 0 in.
  • Whole Plant Traits:
    Plant Type:
    Bulb
    Perennial
    Poisonous
  • Cultural Conditions:
    Light:
    Full sun (6 or more hours of direct sunlight a day)
    Soil Texture:
    High Organic Matter
    Loam (Silt)
    Sand
    Soil Drainage:
    Good Drainage
    Moist
    Occasionally Dry
    Available Space To Plant:
    Less than 12 inches
    NC Region:
    Coastal
    Mountains
    Piedmont
    USDA Plant Hardiness Zone:
    4a, 4b, 5b, 5a, 6a, 6b, 7a, 7b, 8b, 8a
  • Fruit:
    Fruit Type:
    Capsule
  • Flowers:
    Flower Color:
    Blue
    Flower Inflorescence:
    Umbel
    Flower Value To Gardener:
    Fragrant
    Good Cut
    Flower Bloom Time:
    Spring
    Flower Shape:
    Star
    Flower Petals:
    6 petals/rays
    Flower Size:
    < 1 inch
    Flower Description:
    Flowers are small, 6-parted, in a 1-inch cluster at the top of a 20-24 inch naked stem. Blooms late spring in May-June
  • Leaves:
    Leaf Color:
    Green
    Leaf Type:
    Simple
    Leaf Arrangement:
    Alternate
    Leaf Shape:
    Linear
    Leaf Margin:
    Entire
    Hairs Present:
    No
    Leaf Length:
    > 6 inches
    Leaf Width:
    < 1 inch
    Leaf Description:
    Linear green leaves huge the lower stem and often are gone by bloom time.
  • Stem:
    Stem Color:
    Green
    Stem Is Aromatic:
    No
    Stem Cross Section:
    Round
    Stem Form:
    Straight
    Stem Surface:
    Smooth (glabrous)
    Stem Description:
    Tall naked smooth green stem
  • Landscape:
    Landscape Location:
    Meadow
    Landscape Theme:
    Cottage Garden
    Rock Garden
    Attracts:
    Bees
    Butterflies
    Resistance To Challenges:
    Drought
    Problems:
    Weedy
  • Poisonous to Humans:
    Poison Severity:
    Low
    Poison Symptoms:
    Poisonous if ingested. Symptoms may include: Nausea, Vomiting, and Diarrhea.
    Poison Toxic Principle:
    Sulfides
    Causes Contact Dermatitis:
    No
    Poison Part:
    Bark
    Flowers
    Fruits
    Leaves
    Roots
    Seeds
    Stems