Allium cernuum (Nodding Wild Onion)
|Also known as:|
|Habitat:||part shade, sun; open wetlands, swales, lakeshores, wet ditches|
|Bloom season:||July - August|
|Plant height:||1 to 2 feet|
|Wetland Indicator Status:||GP: UPL MW: FACU NCNE: FACU|
|MN county distribution (click map to enlarge):|
|National distribution (click map to enlarge):|
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Pompom-like cluster, 1½ to 2 inches across, at the top of a smooth stem. Flowers are ¼-inch across, light pink to deep rose on long slender stalks, with 6 oval-elliptic tepals (3 petals and 3 sepals all similar) and 6 white stamens with yellow tips. Flowers are mostly bell-shaped with the tepals erect or slightly spreading. The stem is hooked or bent just below the cluster, causing the cluster to hang or nod, and the individual flowers typically also nod to some degree. The flowers and cluster can become more erect as they develop but the tip of the stem remains bent through fruiting. The pair of bracts at the base of the cluster tend to wither away by flowering time.
Leaves and stems:
Leaves are grass-like, up to 22 inches long and ¼ inch wide, keeled along the mid-rib and sheathing the stem near the soil line, appearing to be basal. The central flowering stem, which rises above the leaves, is stiff and smooth. One or more stems may arise from the underground bulbs, which are elongated and taper to the stem.
Fruit is a 3-valved capsule about 1/8 inch across with one shiny black seed per valve.
Nodding Wild Onion most closely resembles Prairie Onion (Allium stellatum). While the bent flowering stalk may be a key difference the distinction is not always so clear, as flowers of both species may initially nod. Other notable differences are: the tepals of A. stellatum flowers are more spreading than A. cernuum (but this can be subtle), the bracts at the base of the A. stellatum cluster persist through flowering, where they usually wither away in A. cernuum, and the underground bulbs of A. stellatum are ovoid and A. cernuum are elongated. Also, while A. stellatum may be found throughout much of Minnesota, A. cernuum is restricted to a few southeast counties, primarily on wooded, north facing slopes above creeks and rivers; A. stellatum habitat is drier and more open, sandy or rocky prairie. According to the DNR, Nodding Wild Onion was listed as a Threatened Species in 1984 when only one population in Mower County was known, but it was downgraded to Special Concern in 2013 after surveys found more than 40 additional populations, mostly in Fillmore County. Nodding Wild Onion is readily available from native plant nurseries and bees simply love it.
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Photos by Peter M. Dziuk taken in a private garden in Ramsey County.
Have you seen this plant in Minnesota, or have any other comments about it?
on: 2017-05-30 16:54:48
I found what I think is the A. Cernuum in my pasture and have transplanted some in my flower gardens. When I uprooted them they have an elongated root. So I think it would be the A. Cernuum.
on: 2017-05-30 17:36:48
Steve, more likely what you have is Allium stellatum, which is a common prairie species in your neck of the woods. The shape of the bulb may be affected by age and other factors.
on: 2017-08-02 17:26:27
Found these beauties on the North shore of the Cedar River just East of the Roosevelt Bridge...2 spots...varied in color from almost white to pink.
on: 2019-08-31 19:57:47
Along pond of nature habitat amidst wild flowers It even has a strong scent almost onion like. It takes awhile for drooping buds to open then this unusual lovely flower. Thank you for a name finally.
on: 2020-08-03 07:06:10
Found these beauties on the west bank of the Upper Iowa River...my sighting from 2017 on the Cedar River was probably Prairie Onion.
on: 2022-02-01 11:59:12
Your photo of the dried flower head gave me an IDea. Could we use the lasting head of seeds as a way to ID the difference between stellatum and cernuum? You never know what you are getting in seed mixes, but I have been thinking I have stellatum -and the winter-lingering dried flowers and seeds are upright. Would cernuum remain downward?
on: 2022-02-01 13:19:01
Frank, I just checked the A. cernuum in my own garden. Seed heads are persisting and most still have at least a little bit of nodding at the tip of the stem, so chances are if all your plants have straight stems at the tip it is likely A. stellatum.