Allium nigrum
Allium nigrum
Black garlic produces dense domes of white flowers with prominent dark green ovaries at the centre of each floret, creating a distinctive two-tone effect. Broad strap-like leaves and sturdy stems make it one of the more structural alliums. Flowers appear in late spring and attract large numbers of pollinators to UK gardens.
Where to plant
Best aspect
Border position
When to plant and expect flowers
Plant
Flowers
How to grow allium nigrum
Plant 10cm deep in autumn in full sun. More tolerant of heavier soils than many alliums but still needs reasonable drainage. Excellent cut flower lasting over two weeks in water. Combine with dark-leaved perennials for contrast.
Soil requirements
Soil type
loam, sand, chalk
Moisture
well drained
pH
neutral, alkaline
Aftercare
Allow foliage to die back naturally after flowering. Remove spent flower heads to prevent self-seeding.
Propagation
- Offsets in autumn
- Seed
Wildlife value
Toxicity
All parts mildly toxic. Contains organosulfur compounds causing gastrointestinal upset.
Common problems
- Slugs and snails
- Squirrels digging up bulbs
Similar bulbs to grow
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