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Pacific Mountain Onion Back to Plant Page
Allium validum

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About Pacific Mountain Onion (Allium validum) Allium validum, known by several common names including swamp onion, wild onion, and Pacific onion, has been previously classified as a member of the lily family, Liliaceae; however, it is now thought of to be in the Alliaceae. Allium validum is native to California. The Allium validum bulb is three to five centimeters long, ovoid and clustered on the short end. The outer coat of the stout rhizome is brown or gray in color, fibrous, and vertically lined. The stem is 50 to 100 centimeters long and angled. There are three to six leaves more or less equal to the stem and the leaves are flat or more or less keeled. There are 15 to 40 flowers with pedicels being seven to twelve millimeters in length. The flower itself is six to ten millimeters, its perianth parts are more or less erect, narrowly lance-shaped, acuminate, and entire with a rose to white color. The stamens are exerted and there is no ovary crest.
Plant Description
Plant Type
Perennial herb

Max. Height
2 ft (0.6 m)


Growth Rate

Flower Color
Purple, Lavender, Pink

Flowering Season

Native Status

Natural Setting
Site Type
Wet meadows


Elevation ?
300' - 13253'

Annual Precip. ?
13.0" - 158.0"

Summer Precip. ?
0.37" - 6.00"

Coldest Month ?
20.7° F - 48.6° F

Hottest Month ?
41.2° F - 69.3° F

Humidity ?
0.95 vpd - 19.95 vpd

Soil Description
Prefers loamy or clay soils. Grows poorly in sandy soils.

Sunset Zones ?
1*, 2*, 3, 4, 5, 6*, 7, 14, 15, 16, 17*, 18, 24

Landscaping Information
Ease of Care
Moderately Easy

Water Requirement ?
Moderate - High
Extremely Low
Very Low
Moderate - High

Propagation ?
For propagating by seed: No treatment.

Common uses
Bee Gardens

Nursery Availability
Rarely Available

Other Names
Common Names
Wild Onion, Swamp Onion, Pacific Onion

Sources include: Wikipedia. All text shown in the "About" section of these pages is available under the Creative Commons Attribution-ShareAlike License. Plant observation data provided by the participants of the California Consortia of Herbaria, Sunset information provided by Jepson Flora Project. Propogation from seed information provided by the Santa Barbara Botanical Garden from "Seed Propagation of Native California Plants" by Dara E. Emery. Sources of plant photos include CalPhotos, Wikimedia Commons, and independent plant photographers who have agreed to share their images with Calscape. Other general sources of information include Calflora, CNPS Manual of Vegetation Online, Jepson Flora Project, Las Pilitas, Theodore Payne, Tree of Life, The Xerces Society, and information provided by CNPS volunteer editors, with special thanks to Don Rideout. Climate data used in creation of plant range maps is from PRISM Climate Group, Oregon State University, using 30 year (1981-2010) annual "normals" at an 800 meter spatial resolution.

Links:   Jepson eFlora Taxon Page  CalPhotos  Wikipedia  Calflora

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