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One Leaf Onion
Allium unifolium
  
About One Leaf Onion (Allium unifolium) 10 Nurseries Carry This Plant Allium unifolium, the one-leaf onion or American garlic, is a North American species of wild onion. It is native to the coastal mountain ranges of California, Oregon, and Baja California. It grows on clay soils including serpentine, at elevations up to 1100 m. Allium unifolium, despite its name, usually has 2-3 flat leaves up to 50 cm long. Bulbs, though, are usually solitary, egg-shaped, up to 2 cm long, often formed at the end of rhizomes spreading out from the parent plant. Scapes are round in cross-section, up to 80 cm tall. Flowers are up to 15 mm across; tepals usually pink but occasionally white; anthers yellow or purple.

Plant Description
Plant Type
Plant Type
Perennial herb

Size
Size
1 - 2.6 ft tall
1 in wide

Form
Form
Upright Columnar

Growth Rate
Growth Rate
Slow

Dormancy
Dormancy
Summer Deciduous

Fragrance
Fragrance
Slight

Flower Color
Flower Color
Lavender, Pink, Yellow, White, Purple

Flowering Season
Flowering Season
Spring

Wildlife Supported
 


Landscaping Information
Sun
Sun
Full Shade, Part Shade

Moisture
Moisture
Low

Summer Irrigation
Summer Irrigation
Never irrigate once established

Nurseries
Nurseries

Ease of Care
Ease of Care
Very Easy

Cold Tolerance
Cold Tolerance
Tolerates cold to 10° F

Soil Drainage
Soil Drainage
Slow

Soil Description
Soil Description
Prefers heavy soils but tolerates a variety of garden soils. Tolerates serpentine soils. Soil PH: 7.0 - 9.0

Common uses
Common uses
Butterfly Gardens, Deer Resistant, Bee Gardens

Companion Plants
Companion Plants
Native grasses, Miner's Lettuce, Dudleya spp,

Sunset Zones
Sunset Zones?
4, 5, 6, 7*, 8, 9*, 14*, 15*, 16*, 17*, 18, 19*, 20*, 21*, 22*, 23*, 24*

Natural Setting
Site Type
Site Type
Pockets of grassland within forest or chaparral, or grassy streambanks with moist clay soils, in the Coast Ranges and foothills

Climate
Climate
Annual Precipitation: 10.5" - 77.7", Summer Precipitation: 0.22" - 1.62", Coldest Month: 40.7" - 51.3", Hottest Month: 58.8" - 79.0", Humidity: 0.04" - 25.23", Elevation: 22" - 4155"

Alternative Names
Common Names: Oneleaf 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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