Allium nigrum
black garlic
A hardy perennial bulb, up to 75cm tall, with grey-green foliage. Large, open, creamy-white flowers, with a central greenish-black ovary, form rounded clusters with a flattened top, up to 10cm across, in early summer
Other common names
broad-leaved onionSynonyms
Allium speciosumAllium multibulbosum
see moreAllium nigrum var. multibulbosum
Allium bauerianum
Allium monspessulanum
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 Grey Silver | |||
|---|---|---|---|---|
| Summer | Cream White | Green Grey Silver | ||
| Autumn | ||||
| Winter |
Position
- Full sun
Aspect
West–facing or East–facing or South–facing
Exposure
Sheltered Hardiness
H5Botanical 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
- Mediterranean
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
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
- Gravel garden
- Architectural
- Cottage and informal garden
- Flower borders and beds
Pruning
No pruning required
Pests
Generally pest free
Diseases
Onion white rot and a downy mildew may occur
Get involved
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