Plant Data Sheet

Nodding Onion, Allium cernuum Roth



Found throughout the US and southern Canada.


Climate, elevation

Moist, cool sites. Found in mountain areas, 600-3500 meters.


Local occurrence (where, how common)

Very common on the west side of the Cascades.


Habitat preferences

Rocky areas, meadows, grasslands, and open forests. Shade intolerant.


Plant strategy type/successional stage (stress-tolerator, competitor, weedy/colonizer, seral, late successional)

Drought tolerant. Pioneer seral stage.


Ben Legler


Associated species

Pseudotsuga menziesii, Juniperus scopulorum, Acer glabrum, Amelanchier spp., Vaccinium spp., Mahonia repens, Holodiscus discolor, Thalictrum occidentale, Arnica cordifolia, Calamagrostis rubescens.


May be collected as: (seed, layered, divisions, etc.)

Seeds, bulbs, transplants


Collection restrictions or guidelines

Collect seed September to October.


Seed germination (needs dormancy breaking?)

Stratification not necessary if planted out in the fall. If not sowing in fall, sowing should occur between February and July. After sowing, container should be covered with plastic and kept at 60-65ºF for 2 weeks, then placed in a cold room for 3-6 weeks. The container should then be kept at 65-70ºF. If after 6-10 weeks, germination doesn’t occur, put back in to cold room for 3-6 more weeks, removing should germination occur. Transplanted seedlings should be placed in cold frame and planted out the following spring.


Seed life (can be stored, short shelf-life, long shelf-life)

One year.


Recommended seed storage conditions

Store this seed for 3-4 months in a cold room of 34-36 degrees F.


Propagation recommendations (plant seeds, vegetative parts, cuttings, etc.)

Seeds, bulb division. 


Soil or medium requirements (inoculum necessary?)

Must be kept moist.


Installation form (form, potential for successful outcomes, cost)

Bulb divisions.


Recommended planting density

Twelve-inches apart.


Care requirements after installed (water weekly, water once etc.)

Keep soil moist.  


Normal rate of growth or spread; lifespan

To 20 inches tall, less than one-foot across, medium growth rate. One to three-year lifespan.


Sources cited:


1.       Royal BC Museum:

2.       Burke Museum Herbarium:

3.       Flora of North America:

4.       Native Plants Propagation Protocol Database:

5.       Thompson and Morgan:

6.       Native Crops Urban Agriculture:

7.       ECOS Guide to the Ecology of the Northern Rockies: 

8.       Northeast Oregon Hatchery Program Grande Ronde-Imnaha Spring Chinook Hatchery Project: Biological Assessment:

9.       Plant Indicator Guide for Northern British Columbia: Boreal, Sub-Boreal, and Subalpine Biogeoclimatic Zones: 

10.   Mississippi National River and Recreation Area:



Data compiled by

Lorraine Brooks

May 10, 2006