Giant onion
Allium giganteum · Amaryllidaceae
📷 W. Bulach · CC BY-SA 4.0
⚠️ Bulbes et feuilles peuvent endommager les globules rouges des chiens et surtout des chats ; le risque dépend de la quantité ingérée, crue ou cuite.
The gardener's calendar
Ideal time to plant giant onion: set it out when the soil is neither frozen nor waterlogged, and water generously as it establishes.
ID card
- Scientific name
- Allium giganteum
- Family
- Amaryllidaceae
- Plant type
- Perennial bulb
- Adult height
- 150 cm
- Flowering
- May to June
- Foliage
- Deciduous
- Hardiness
- Very hardy (down to -20°C)
- Origin
- Mountains of Tajikistan and Afghanistan
✓ Taxonomy verifiedSource: AI estimate · hardiness: reliability high.
Expert tips
The key tip
Plant bulbs in autumn, deep enough (15 cm) in well-drained soil. In humid areas, raise the bed or improve drainage with sand.
The common mistake
Rotting in overly wet or poorly drained soil in winter and spring—the silent killer of giant garlic.
The pro's trick
Install a discreet stake right at planting time, before the stem grows: it'll stay hidden and won't damage roots later.
Care
Sunlight
Giant garlic thrives in full sun, with at least 6 hours per day. A south or west-facing exposure is ideal to stimulate spectacular flowering. Light shade is tolerated but will reduce vigor and blooming.
Watering
Water regularly during spring growth, keeping the soil moist but without waterlogging. Gradually reduce watering in summer after flowering. A dormant planted bulb requires almost no water during winter dormancy.
Soil
Prepare well-drained soil rich in organic matter. Chalky or neutral soil is ideal. Amend with well-decomposed compost at planting time. Avoid heavy, waterlogged soils that promote bulb rot.
Fertilizing
Apply balanced fertilizer at the start of the season, as soon as the first leaves emerge. A potassium-rich fertilizer when the flower buds form promotes denser blooming. One annual application is sufficient to maintain vigor.
Pruning and maintenance
No pruning is necessary. Remove spent flowers if you wish to encourage seed production, otherwise leave them to dry on the plant for ornamental effect. Clean up dead foliage in late autumn.
Diseases and pests
Giant garlic is generally very healthy. Bulb rot can occur in overly moist soil. Watch for aphids in spring, which are easily eliminated with a water spray. Chemical treatment is usually unnecessary under normal conditions.
Did you know?
Allium giganteum is one of the largest garlic species, producing violet spherical umbel flowers that can reach up to 15 cm in diameter and attract plenty of pollinators. In the Himalayan mountains, this giant garlic has long been harvested locally for its medicinal properties. Its spectacular inflorescence makes it highly sought after by amateur gardeners who love unusual flowers and remarkable vertical structures in the garden.
Where to buy it
Plant the bulbs in autumn for spring flowering. Pick a plant with healthy foliage and roots that are not exposed. Best time: from September to November.
Add this plant to my garden →Plants from the same family
- RamsonsAllium ursinum
- ChivesAllium schoenoprasum
- Sand leekAllium scorodoprasum
- Elephant garlicAllium ampeloprasum
- OnionAllium cepa
- Belladonna lilyAmaryllis belladonna
Tips generated and checked by Viridia — adapt them to your local climate.