About
Allium 'Firmament' is a bulbous perennial that reaches heights of up to 80 cm. It features narrow, strap-like foliage. In the summer months, sturdy stems support large, spherical clusters of flowers, measuring up to 12 cm across, adorned with deep purple, star-shaped blooms.
About the genus
Allium consists of bulbous herbaceous perennials characterized by a pronounced onion or garlic aroma. They feature linear, strap-like, or cylindrical leaves that arise from the base. The flowers, which can be star-shaped or bell-shaped, are arranged in an umbel atop a stem that lacks leaves.
Growing conditions
- Sunlight
- Full sun
- Soil type
- Chalk, Clay, Loam, Sand
- Soil pH
- Acid, Alkaline, Neutral
- Soil moisture
- Moist but well-drained, Well-drained
- Aspect
- West-facing, South-facing, East-facing
- Exposure
- Sheltered
- UK hardiness
- H5
Plant details
- Plant type
- Bulbs
- Habit
- Clump forming
- Foliage
- Deciduous
- Height
- 0.5-1 metres
- Spread
- 0.1-0.5 metres
- Time to full height
- 2-5 years
- Suggested uses
- Cottage and informal garden, City and courtyard gardens, Gravel garden, Coastal, Patio and container plants, Wildlife gardens
- Fragrance
- Foliage
Care notes
- Cultivation
- Grow in full sun and fertile well-drained soil. It is best to grow in containers where garden soil is heavy clay and prone to saturation over winter. See allium cultivation
- Pruning
- No pruning required, other than to remove old flowered stems and foliage
- Propagation
- Propagate by offsets which can be carefully detached by lifting the bulb after flowering has finished. See bulb propagation
- Pest resistance
- May be susceptible to allium leaf miner and onion fly
- Disease resistance
- May be susceptible to onion white rot, and onion downy mildew