The oldest public wildflower garden in the United States
Prairie Wild Onion (Autumn Onion)
Allium stellatum Fraser ex Ker Gawl.
Wild Onion (Alliaceae)
Late Summer to Early Autumn
Wild Onion is a native perennial forb growing to 1-1/2 feet high to the top of the erect flowering stem.
The leaves are all basal and form a rosette, rising in a vase shape before bending outward and downward. Leaves are linear, with parallel veins, flat, solid, with a center raised ridge. They are slightly shorter than the flower stalk and have a basal sheath, which is usually not seen above ground level. They dry up after flowering time.
The inflorescence is an umbel of numerous (9 to 40) stalked flowers. The umbel, 2 to 3 inches wide, is atop a round smooth greenish scape (a flowering stem that arises directly from the roots). The entire flower head may nod in the bud stage as the top of scape bends over, but it then becomes erect at flowering unlike Allium cernuum which remains nodding with the flowers opening downward. The base of the umbel has two thin lanceolate shaped bracts.
The flowers are pinkish or whitish-pink, to even purplish is strong sunlight, small and hemisphere shaped, 6-parted, about 1/4 inch long with three sepals and three petals combined to form six tepals. The margins of the 3 outer tepals are incurved but all six are spreading creating a star-like shape, not a bell shape. There are six exserted stamens that have pink filaments and yellowish anthers. The single style is about as long as the stamens and has a blunt but scarcely thickened tip. The 3-sectioned ovary is greenish and has a conspicuous crest.
Fruit: The flowers produce a 3-chambered seed capsule, not bulblets. The capsule elongates and eventually exposes three roundish black seeds that can have a dull surface. These are usually wind dispersed. Seeds require 60 days of cold stratification for germination.
Habitat: Wild Onion grows from an ovoid shaped bulb and finer fibrous roots. Bulbs are usually clustered in groups of 1 to 5+. There usually is some grayish or brownish membranous material attached to the outside of the bulb. Both the leaves and the bulb are considered edible, but much stronger of flavor than garden onions. The Chippewa word for the plant meant "prairie skunk plant" referring to the odor. The plant prefers full sun and dry conditions with well drained soils - mesic to dry moisture conditions. The fibrous roots go somewhat deep, so dig deeply if moving the plants. In dense areas it is best on the edges as it may not compete with more aggressive plants.
Names: The genus, Allium, is Latin for garlic. The base word of the species name, stellatum, means 'starry' referring to the open flower shape. The author names for the plant classification are a bit complex. First to publish was 'Fraser’ who was John Fraser (1750-1811) Scottish botanist who collected specimens from North America and the West Indies which he exported back to Europe. He was a commissioned plant collector for the Czarina Catherine of Russia. His work was amended by ‘Ker Gaul.’ who was John Bellenden Ker Gawler (1764?-1842), English botanist who published several botanical works and edited Edward’s Botanical Register from 1815 to 1824.
All older references will list this species in the Lily Family (Liliaceae). Some botanists has created a new family specifically for the New World Allium. Some others have included a few Old World Allium in the new family and some have only included a portion of the New World Species. This family arrangement is still in flux, although the Minnesota Authorities at the U of M Herbarium have adopted the new family name for the 7 New World Allium. Flora of North America has noted the many proposals but not yet published them.
Comparisons: Of the native Alliums with similar flowers two can be compared. First is Wild Garlic, Allium canadense, but only likely to be confused before flowering. Unlike the other wild onions, the inflorescence develops small bulblets. Also, the leaf sheaths are above ground and the leaves are broad. The most confusing species will be Nodding Wild Onion, A. cernuum, but there the flower umbel is always nodding when in flower and the tepals (pointing downward) form a bell shape, not a star shape. Also, the root bulb is more elongate.
Above: Wild Onion in the bud stage when the scapes nod. They become erect at flowering time. Historical illustration by Wm. Curtis.
Below: Flowers from mid-July to mid-August. The tepals are spreading with pointed tips, creating a star shape. Note in the 2nd photo the greenish 3 chambered ovary.
Below: 1st photo - Black seeds are released from a three-parted capsule. 2nd photo - At flowering time the umbel is always erect and the flowers face upwards.
Below: 1st photo - The seeds produced in the 3-part capsule are black and roundish. 2nd photo - The leaves have parallel veins with a slightly raised center section.
Below: Bulb comparison of A. stellatum (left) and A. cernuum (right). The former is more conical and usually has some grayish or brownish membranous material attached to the bulb.
Notes: Wild Onion is not indigenous to the Garden but was introduced in Sept. 1930 when Eloise Butler brought in plants from Barksdale WI. Strange source, since it is native to Minnesota, mostly the western half of the state, plus eastward in the central region to the Wisconsin border including Hennepin, Dakota and Washington Counties. In North America the species is found in the central part of the continent, from Saskatchewan, Manitoba and Ontario in Canada, south to Texas, east as far as Indiana and Tennessee. In some states it is considered a noxious weed, in others - endangered. Martha Crone noted planting 18 of them in 1945 but the plant did not appear on her 1951 census.
Prairie Wild Onion is one of is one of six Allium species known to Minnesota plus one which is considered a garden hybrid. The six natives are: A. canadense, Wild Garlic; A. cernuum, Nodding Wild Onion; A. schoenoprasum, Wild Chives; A. stellatum, Prairie Onion; A. textile, White Wild Onion; and A. tricoccum, Wild Leek: Four of the species are found in the Garden - A. stellatum and the three with links to information sheets.
Medicinal Lore: Onions have a long history in folk medicinal use. In Minnesota, Frances Densmore (Ref. #5) in her study of the Minnesota Chippewa, reported the root was used to make a decoction that, after some sweetening, was given to children to drink to treat a cold.
Eloise Butler wrote of the wild onions: ". . . pink balls of fairy grace lifted on slender, leafless stalks give a magical brilliancy to the billowing grasses of large expanses of the prairie. Do not be disconcerted by the name. The onion is, after all, a sort of lily, considered by every one a flower queen, and the odor is not perceptible, except when the plant is bruised. The leaves of this Allium are very narrow, unlike those of the early leek, so abundant in the wood in early spring." Published Aug. 20, 1911, Minneapolis Sunday Tribune.
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References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Identification booklet for most of the flowering forbs and small flowering shrubs of the Eloise Butler Wildflower Garden. Details Here.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"