On these pages photos of North American Allium species will be featured. There are approximately 130 taxa in North America, almost half of which occur in California as the center of diversity. Besides a few species that are widely grown, namely Allium cernuum (nodding onion), the Californian A. unifolium (popularized by the Dutch bulb trade) and the lesser known A. stellatum (prairie onion), the North American onion species have been largely ignored by the horticultural world. There are also about 15 species native to Mexico, similarly rare or absent from horticulture. Eastern American species generally need a cool - cold winter dormancy period with some to lots of rain. Western American species, especially those in the Pacific States follow a Mediterranean pattern where they need a moderately cold wet winter and a cool dry summer.
Taxonomically, there have been few changes in American species. A phylogenetic study by Nguyen et al, 2008 found that North American alliums are distinct from European species and those occurring in the California Floristic Province (CFP) are mostly distinct from eastern American species. California holds a wide variety of species whose forms are distinctive in leaf and bulb coat morphology. Species related to Allium falcifolium form falcate leaves whereas species related to Allium jepsonii form a single leaf from which the inflorescence emerges on the side. Many CFP species have also adapted to a special type of soil called serpentine which is very high in minerals such as magnesium, making it toxic to many plants. Some Allium species are so adapted that they can only be found on serpentine soil in the wild.
American alliums from D-H are found on this wiki page.
American alliums A-C – American alliums I-M – American alliums N-R – American alliums S-Z
Allium diabolense (syn. Allium fimbriatum var. diabolense) is a California species found south of San Francisco Bay in the Inner South Coast ranges where it is often found growing in serpentine. It has white flowers with pink midveins and one leaf. Photos 1-2 were taken by Mary Sue Ittner of plants growing on Figueroa Mountain in Santa Barbara County.
The photos below were taken by Nhu Nguyen of plants in cultivation. Photos 1-2 were taken at the UC Botanical Garden.
Allium dichlamydeum grows near the coast in Northern and central California. Since they grow on cliff faces where there is little soil, their bulbs do not bury very deep. It is one of the latest blooming of the Californian onions. These pictures by Bob Rutemoeller show it in bud on a coastal bluff, in bloom in the same spot a few weeks later, and a close-up. The fourth picture shows it growing in a wild rock garden where it would be difficult for predators to get it, and almost two months after the first pictures in mid July 2003 it is still in bloom, now with Dudleya farinosa blooming at the same time. The final picture is a close-up of the two plants in bloom in another year.
Photo 1 below shows the plants growing in a raised bed in Mary Sue Ittner's garden. Photos 2-3 by Mark McDonough show two views of this species growing in his Massachusetts garden. Photos 4-6 were taken by Nhu Nguyen of plants growing in a small pot in California. The bulbs divide well and produces a wonderful show.
Allium eulae (synonym A. fraseri var. eulae), is native to Texas where it is endemic to the Texas Highland Lake region, growing in seepy places, although hardy in more northern climates and growing well in normal well drained garden soil in full sun. Photo by John Lonsdale.
Allium falcifolium occurs on serpentine soils and outcrops from San Francisco Bay to Oregon. It is often found on slopes with excellent drainage. It is also never found too far away from oak trees, relying on the organic matter from decaying oak leaves. The hummus contents can range from 50% - 20% in the wild. There are two flower forms of this species, with the more common magenta pictured below and a more rare and often elusive white form. 1st photo by Jane McGary, 2nd by Mary Sue Ittner, and the last a macro of a specimen grown by Nhu Nguyen.
Habitat photos from Nhu Nguyen are shown below. Photos 1-2 shows the habitat in Napa County where they flower with Eschscholzia caespitosa amongst the serpentine rocks. Photo 5 illustrates the sickle shaped leaves.
The photos below of a white/pink form were taken by Nhu Nguyen on Mount Diablo in Contra Costa County, CA. This form interestingly does not grow on serpentine. Photo 1 shows wonderfully curly leaves.
Allium fimbriatum is restricted to California where they grow on dry, well-drained slopes. There are three varieties of the species.
Allium fimbriatum var. fimbriatum has rose purple flowers with flaring tips. It grows in gravelly volcanic or serpentine clays. The photos below were taken by Nhu Nguyen in Pinnacles National Monument.
Allium fimbriatum var. mohavense is only found in the Mohave Desert. It has flowers that are white to pink to light lavender.
Allium fimbriatum var. purdyi is restricted to serpentine soil in the inner North Coast ranges. Flowers are white to pale lavender with darker midveins. The first three photos were taken by Nhu Nguyen. The second photo shows developing into seeds and the third photo shows a serpentine slope where they occur. The fourth and fifth photos were taken by Mary Sue Ittner. The fourth was taken of plants blooming in Colusa County, April 2005 and the fifth shows flowers of plants grown from seed collected in Lake Co. at 2150' in crumbly, flaky serpentine talus flats.
Allium glandulosum - a Mexican species that blooms in late summer and autumn with dark, metallic red flowers. The plant shown here in several photos was originally collected in central Mexico at high elevation in swampy soil. Difficult to photograph well and I'm sorry about the poor shots. The first two show the true red flowers close up, the last shot show an entire potted plant. Photos by Mark McDonough.
Allium gooddingii - another of the moisture-loving western species, this one from Arizona and New Mexico, growing at high elevation swampy or marshy spots, or alongside streams. It's a slender plant, with a few-flowered upright spray of intense red-purple flowers. The gray stems reach about 18" (45 cm). In the photo we see the gray foliage of A. plummerae in back and a flower head of A. flavum. Photo by Mark McDonough.
Allium haematochiton is found both on dry slopes and ridges from the south coast ranges of California into northern Baja, but also is found in seasonally moist, grassy meadows. It is tolerant of summer water and almost evergreen in those conditions. If dormant it is one of the first to appear in the fall and long blooming. It is also known to grow on serpentine. The first photo by Bob Rutemoeller and the second by Kristina Van Wert from the Mendocino Coast Botanical Gardens collection. The last two pictures below are of bulbs grown and photographed by Nhu Nguyen. The second photo shows the blood-red skin of the bulbs, giving it the specific epithet "haematochiton" or "red tunic" in Greek, although not all forms will have the red color.
The pictures listed below were taken at Figueroa Mountain April 2005 by Mary Sue Ittner.
Allium hickmanii is restricted to the central coast of California from the Monterey Peninsula to San Luis Obispo County. It is a relatively small onion with very thin leaves. It grows on grassy, wooded slopes. Photos by Nhu Nguyen at the UC Botanical Garden.
Allium howellii is a mostly southern California species with three varieties. It has exserted stamens and prominent ovary crests.
Allium howellii var. clokeyi grows on open slopes in desert sagebrush scrub. It has white flowers , sometimes with pink midviens. Photos by Mary Sue Ittner of the flower and the bulb (shown on a 1 cm. square grid).
Allium howellii var. howellii is a common species with pale lavender flowers that grows on grassy slopes. It is distinguished from the other varieties by its thin stem.
Allium howellii var. sanbenitense grows on thinly grassy slopes in serpentine soils in San Benito and Fresno counties.
Allium hyalinum is a California onion with small starry flowers that sparkle in bright sun. It is found in grasslands moist in the spring in the central and southern Sierra foothills. There are generally two forms, a white and a pink. This species is easy in culture and multiples very well.
The photos below were taken by Nhu Nguyen on CA HW49 near Yosemite National Park. The plants were growing out of a thin organic mat on rocky surfaces where a seep occurs.
Below are photos of a white form. Photo 1 by Bob Rutemoeller and 2 by Kristina Van Wert were taken from the Mendocino Coast Botanical Gardens collection. Photo 3-6 were taken by Nhu Nguyen at the Tilden Botanical Garden?.
Photo 1 was taken by Nhu Nguyen. Photo 2 from Mary Sue Ittner shows the small bulbs on a 1cm grid.
The photos below by Nhu Nguyen shows a pink form.
Allium index – American alliums A-C – American alliums I-M – American alliums N-R – American alliums S-Z – Allium flavum Relatives – Allium hybrids – Big Ball alliums – Blue alliums – chives – Domed alliums – Drumstick alliums – Miscellaneous alliums A-E – Miscellaneous alliums F-M – Miscellaneous alliums N-R – Miscellaneous alliums S-Z – Rhizomatous alliums