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Ornamental onion

Allium aflatunense

Common names:
ornamental onion

Content Detail

Ornamental onion is an easy-to-grow perennial for a sunny spring garden. Although a bulb, it is often purchased as a potted plant. Long, slender, flat leaves give way to large, multi-flowered clusters of purple flowers. Attracts butterflies and other pollinators.

  • Family (English) Amaryllis
  • Family (botanic) Amaryllidaceae
  • Tree or plant type Perennial
  • Native locale Non-native
  • Size range Medium plant (12-24 inches), Large plant (more than 24 inches)
  • Light exposure Full sun (6 hrs direct light daily), Partial sun / shade (4-6 hrs light daily)
  • Hardiness zones Zone 4, Zone 5 (Northern Illinois), Zone 6 (City of Chicago), Zone 7, Zone 8, Zone 9, Zone 10
  • Soil preference Alkaline soil, Moist, well-drained soil
  • Tolerances Alkaline soil, clay soil, Dry sites, Occasional drought, Road salt
  • Season of interest early spring, mid spring
  • Flower color and fragrance Pink, Purple
  • Shape or form Narrow, Upright
  • Growth rate Fast

Size and form:

Ornamental onion is a bulb often purchased as a potted plant. Strap-like leaves reach 2 to 3 feet long and the flower stalk can reach 3 feet high.

Native geographic location and habitat:

It is found at the forest edge and natural areas of Central Asia.

Pollinators and wildlife:

Bees and butterflies are attracted to it. 

Leaf description:

It has long, slender, flat or cylindrical leaves with hollow centers up to 3 feet long. The leaves have an onion or garlic odor.

Flower description:

It produces large, multi-flowered umbels with small, six-parted clusters of purple flowers in late spring to early summer. Flowering lasts for two to three weeks.

Fruit, cone, nut, and seed descriptions:

It has small black seeds within a seed capsule.

Plant care:

Ornamental onion grows best in full sun to part shade and moist well-drained soils. Ornamental onion is tolerant of clay, loam, and sand, but does not like wet soil. Plant bulbs in fall for spring blooms. The flower stalk can be cut back after flowers to avoid seeds. This plant has poisonous characteristics.

List of pests, diseases and tolerances:

The bulbs are disease-free, but they will rot in wet soil. Deer, chipmunks, and rabbits tend to avoid the bulbs.

Purple Sensation ornamental onion (Allium aflatunense ‘Purple Sensation’):

It grows 20 to 30 inches high and has violet purple flowers.

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