Bulbs

Allium
ornamental onion

- Height 1-5 ft (30-150 cm)
- Planting distance 3-12 in (7.5-30 cm)
- Flowers summer
- Any well-drained soil
- Sunny, open site
- Bulbs available fall
- Hardy zones 4 or 5-10

Ornamental onions are becoming increasingly popular because of their easygoing nature, tough constitution, and long-lasting flowers. The flowers appear in summer and, depending on the cultivar, range in color from white, yellow, and blue to deep lilac and rose. Some alliums are ideal for mixed or herbaceous borders, other for rock gardens, window boxes, and even indoor displays. Their onionlike smell is apparent only when the leaves and stems are bruised.

Popular species and cultivars
Allium christophii (syn. A. albopilosum) is best grown among herbaceous plants that hide its untidy gray-blue leaves without giving too much shade. Plant the bulbs 4-5 in (10-13 cm) apart. In early summer the large heads of striking star-shaped lilac-pink flowers appear on stems that are 2 ft (60 cm) tall. The seed heads that follow in fall and winter are good for cut flower arrangements. Allium caeruleum (syn. A. azureum) has densely packed balls of starlike flax-blue flowers among long, thin midgreen leaves in early summer and midsummer. Set the bulbs 6 in (15 cm) apart. The flowers are carried on 2-3 ft (60-90 cm) high stems and thus are suitable for cutting. Allium giganteum stands well above most other herbaceous plants, often reaching an impressive height of 5 ft (150 cm). It is grown for its large decorative flower heads: balls of purple star-shaped florets, which appear in early summer. Like many of the ornamental onions, it has long, thin gray-blue leaves. Plant 9-12 in (23-30 cm) apart. Allium moly forms a vivid display in early summer and midsummer with its bright yellow star-shaped leaves. It reaches only 1 ft (30 cm) high but is particularly invasive, so avoid planting it among small, delicate plants. Space the bulbs 4 in (10 cm) apart. Allium ostrowskianum (syn. A. oreophilum), a popular member of the family, reaches only 1 ft (30 cm) high. When planted 3 in (7.5 cm) apart, it can spread rapidly. The small rose-colored flowers and drooping gray-blue leaves are excellent for livening up a rock garden in early summer. Allium roseum has elegant rose-pink star-shaped flowers, which come out in early summer. It reaches 2 ft (60 cm) high and has long, broad midgreen leaves. Plant the bulbs 4 in (10 cm) apart in a sunny, sheltered site.

Bulbs