Allium sphaerocephalon
round-headed leek
A tall perennial with a tuft of narrow basal leaves to 30cm long, and long-stalked, dense, rounded heads of pink or reddish-brown flowers in summer
Size
Ultimate height
0.5–1 metresTime to ultimate height
2–5 yearsUltimate spread
0.1–0.5 metresGrowing conditions
Moisture
Moist but well–drained, Well–drainedpH
Acid, Alkaline, NeutralColour & scent
| Stem | Flower | Foliage | Fruit | |
| Spring | Green | |||
|---|---|---|---|---|
| Summer | Brown Pink | Green | ||
| Autumn | ||||
| Winter |
Position
- Full sun
Aspect
South–facing or North–facing or West–facing or East–facing
Exposure
Sheltered Hardiness
H6Botanical details
- Family
- Amaryllidaceae
- Native to the UK
- No
- Foliage
- Deciduous
- Habit
- Bushy
- Genus
Allium are bulbous herbaceous perennials with a strong onion or garlic scent, linear, strap-shaped or cylindrical basal leaves and star-shaped or bell-shaped flowers in an umbel on a leafless stem
- Name status
Correct
- Plant range
- Eurasia, Africa
How to grow
Cultivation
Easy to grow in fertile well-drained soil. Add grit when grown in clay soils to improve drainage. See allium cultivation for further advice
Propagation
Propagate by seed, sowing in containers in a cold frame when just ripe or in the spring. Alternatively, remove offsets in autumn
Suggested planting locations and garden types
- City and courtyard gardens
- Coastal
- Cottage and informal garden
- Patio and container plants
- Flower borders and beds
Pruning
No pruning required
Pests
Generally pest-free
Diseases
Onion white rot and a downy mildew may occur
Get involved
The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.