Ornamental onion, Allium Alliums include a wide range of plants, from chives and small bulbs with tiny flowers to drumsticks with stout vertical stems topped with balls of colour.

In this article

Recommended varieties

Growing tips

Where to see them

Alliums add impact to early summer borders and can be dried for winter decoration. They come in a wonderful range of colours including purple, buttercup yellow, pinks, white and shades of cornflower blue.

Alliums are extremely easy to grow, invariably needing a place in full sun right at the front of a border.

Large drumstick alliums need to be planted in small groups of five or seven so they really stand out:

• Allium cristophii: blockbuster with large purple heads measuring 20cm (8in) wide. These make superb cut flowers and have an almost metallic sheen on the stout stems, which reach knee height. Best placed in the spaces between border perennials to disguise its dying foliage. Has been given the Royal Horticultural Society's Award of Garden Merit (AGM).
• A. 'Globemaster': another giant with huge spherical 20cm (8in) purple heads, each of which has up to 1,000 star-shaped blooms. Has been awarded the AGM.
• A. schubertii: real stunner with round flower-heads measuring 30cm (1ft) wide, which resemble the starburst of a firework. The stems that pop out of the inner globe are thought to aid propagation by propelling the seed-heads.

Small drumsticks are shorter with smaller flower-heads and are best in rock gardens or right at the front of a border:

• A. caerulum: has small round blue heads just 2.5cm (1in) wide. Awarded the AGM.
• A. karataviense: a pair of broad, greyish leaves last a long time and complement the 8cm (3in) wide pale pink flowers. Try among old-fashioned pinks and variegated sage. Awarded the AGM.
• A. sphaerocephalon: small, 2.5cm (1in) wide, pink to reddish-brown drumstick on long wiry stems. The flowers are densely packed and remain in bloom for many weeks.

Ordinary alliums aren't as showy as the drumsticks, but are equally delightful for a low-key, carefree show:

• A. nigrum: don't be misled by the name - this has white flowers. Nigrum refers to the dark, greenish-black flower centres. The flower-heads are dome-shaped and held on tall stems about 35cm (14in) high.
• A. schoenoprasum: the common chive can be grown in herb gardens but is also terrific at the front of a border, especially in its deep pink form, 'Forescate'.
• Nectaroscordum siculum: although no longer an allium, this a close relative reclassified by botanists. Its large bells are subtly shaded pink and cream, and stand out well on tall stems. The flowers begin in an upright position, hang gracefully when open, then become more upright as they develop into seed-heads.

Site and soil preferences

In the wild, alliums often grow in poor, stony ground and they don't need pampering in the garden. Average soil is fine, but it must be free-draining.

Alliums in pots

Even gardeners with tiny gardens can grow alliums in containers. Always use a reasonably deep container, especially for larger varieties. Plant at three times the depth of the bulb in well-drained compost (this also applies when planting in the open ground).

The container plants will need repotting into fresh compost every year, but you don't need to do any more than this. They shouldn't require extra feeding, either, as long as their foliage is left to die back naturally. This enables them to build up energy for the following year. Like some other bulbs, they're naturally long-lived and survive for years if left undisturbed.

With large drumstick alliums, the dying foliage can be disguised behind a few pots of bushy annuals or a clipped box for a more formal look.

National Collections of alliums:

P Davies
6 Blenheim Road
Caversham, Reading
Berkshire RG4 7RS
By appointment only