Overview

Allium giganteum is a plant with a clump-forming habit in the genus Allium, part of the Amaryllidaceae family, with deciduous foliage. It typically grows around 1.5 metres tall. Allium giganteum grows best in full sun, and tolerates most soils and any pH. Its UK hardiness is rated H6. Suggested uses include borders, cut flowers, dried flowers and architectural planting.

About

Allium giganteum, common name giant onion or giant leek, is an Asian species of onion in the amaryllis family (Amaryllidaceae), subfamily Allioideae, native to central and southwestern Asia but cultivated in many countries as a flowering garden plant. It is the tallest species of Allium in common cultivation, growing to 1.5 metres (4.9 ft).

Wikipedia contributors, CC BY-SA 4.0Allium giganteum

About the genus

Allium is a large genus of monocotyledonous flowering plants with 1112 accepted species, making Allium the largest genus in the family Amaryllidaceae and among the largest plant genera in the world. Many of the species are edible, and some have a long history of cultivation and human consumption such as the onion, garlic, scallions, shallots, leeks, and chives.

Wikipedia contributors, "Allium", CC BY-SA 4.0Allium

Growing conditions

Best soil and position for Allium

Sunlight
Full sun
Soil type
Loam, Sand, Chalk
Soil pH
Acid, Alkaline, Neutral
Soil moisture
Well-drained
Aspect
South-facing, East-facing, West-facing
Exposure
Sheltered
UK hardiness
H6

Plant details

Allium giganteum size, habit and characteristics

Habit
Clump-forming
Foliage
Deciduous
Height
1.5 metres
Suggested uses
Borders, Cut flowers, Dried flowers, Architectural planting

Care notes

Pruning and caring for Allium giganteum

Propagation
Offsets, Seed
Pest resistance
Allium leaf miner, Onion fly
Disease resistance
Onion white rot, Onion downy mildew, Leek rust

Frequently asked questions

Where is the best place to plant Allium giganteum?

Allium giganteum prefers full sun. It suits sheltered positions.

What soil does Allium giganteum need?

Allium giganteum is adaptable and grows happily in most soil types, including loam, sand and chalk. It is happy in soil of any pH. Aim for soil that stays well-drained.

How big does Allium giganteum grow?

Allium giganteum reaches a height of 1.5 metres.

Is Allium giganteum hardy in the UK?

Allium giganteum has an RHS hardiness rating of H6, meaning it is very hardy, tolerating -20 to -15°C across most of the UK.

How do I propagate Allium giganteum?

Offsets, Seed.

More in the Allium genus

Browse all Allium