About

Allium altissimum is a deciduous perennial that blooms early in the season. It features narrow, strap-like leaves that are a medium green in color, though they typically begin to fade and brown as the flowering period commences. This species produces rounded clusters of purple-pink blossoms atop upright stems that can reach heights of up to 1.1 meters. To enhance the overall appearance of the plant, it is advisable to position these bulbs near other plants that can effectively obscure the wilting foliage as it declines.

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, Loam, Sand

Soil pH

Acid, Alkaline, Neutral

Soil moisture

Moist but well-drained, Well-drained

Aspect

South-facing, West-facing

Exposure

Sheltered

UK hardiness

H6

Plant details

Plant type

Bulbs

Habit

Clump forming

Foliage

Deciduous

Height

1-1.5 metres

Spread

0.1-0.5 metres

Time to full height

1-2 years

Suggested uses

Cottage and informal garden, City and courtyard gardens, Wildflower meadow, Wildlife gardens

Fragrance

Foliage

Care notes

Cultivation

Easy to grow in full sun and a 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 seed, sowing in containers in a cold frame when just ripe or in the spring and by offsets which can be carefully detached by lifting the bulb after flowering has finished. See bulb propagation

Pest resistance

May be susceptible to slugs, snails and allium leaf miner

Disease resistance

May be susceptible to onion white rot, and onion downy mildew