WSU Clark County Extension

PNW Plants Searchable, categorized images

Giant Allium

Scientific name: Allium giganteum

Type:Bulbs, corms, tubers, rhizomes
Plant Requirements
Zone:5 to 8
Plant Characteristics
Height:4 ft
Width:2 ft
Bloom:Showy flowers
Bloom Time:May to June
Bloom Color:Lavender
Additional Characteristics



Wildlife value

Description Giant Allium, or ornamental onion as it is often called, is related to the garden onions, garlic and leeks. It is grown for the dense clusters of flowers, which look like lollipops.

This is a perennial derived from a large (2”-3” diameter) underground bulb. In the spring grayish-green strap shaped leaves emerge from the bulb in the form of a rosette. Leaves can attain a height of 18”.

From the center of the leaves a thick flower stalk emerges and grows to a height of 4’. At the top of this stem a dense softball-sized flower cluster emerges, consisting of numerous star-shaped lilac purple florets. These flowers last as long as 3 weeks if they are protected from strong winds. The entire plant has an onion smell if one brushes against the flowers or the leaves. The leaves start to decline as soon as the flowers emerge.

Has not specific site requirements. This species is considered drought tolerant once established.

Pest free as long as it is planted on well-drained soils.
For assistance, contact Dr. Charles Brun (, (360) 397-6060 5701
Computing and Web Resources, PO Box 6234, Washington State University, Pullman WA 99164-6234