BBC Gardeners' World

Plant details

• Common Name: Ornamental onion
• Genus: Allium
• Species: cristophii
• Skill Level: beginner
• Exposure: full sun
• Soil type: well-drained/light
• Height: 0.6m
• Spread: 0.15m
• Flowering period: July to August

There are several ball-headed kinds of flowering onion, and this is the largest and perhaps the most eye-catching of them all. Sometimes called the 'Star of Persia,' it is a native of Turkey and Iran, and loves a warm sunny site where it will tolerate competition from tree and hedge roots. Each huge, spherical flower-head contains up to 80 purple flowers with slightly flattened petals that emphasise the perfect ball shape. As these fade, they resemble brown stars, and the complete stem will last for many weeks as part of a dried flower arrangement. The Royal Horticultural Society has given it the Award of Garden Merit (AGM).