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 G-H are found on this wiki page.
Allium geyeri is native to Pacific coast North West America damp meadows. Named for the German botanist Charles A. Geyer who travelled across the Western USA in 1843. Photograph by Rimmer de Vries.
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.
Photo below by Wietse Mellema.
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 was taken by Bob Rutemoeller. 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.
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 var. clokeyi grows on open slopes in desert sagebrush scrub. It has white flowers , sometimes with pink midveins. 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.
Allium index - Allium flavum Relatives - American alliums A-B - American alliums C - American alliums D-F - American alliums I-M - American alliums N-R - American alliums S-Z - 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