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 recent 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 distinct from eastern American species. California holds a wide variety of species whose forms are distinctive in leaf 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 I-M are found on this wiki page. American alliums A-C – American alliums D-H - American alliums N-R – American alliums S-Z
Allium jepsonii is a Californian species that has a single, terete, rat-tail-like leaf, from which pops out a flower stem from a basal incision near the base, and a small head of white, lightly nerved flowers in July. Needs excellent drainage. The stems tend to recline, as shown in the image. The species is often found on serpentine. For a while it was listed as an endangered species and has now been delisted due to discoveries of new populations. Photos by Mark McDonough, Mary Sue Ittner and Nhu Nguyen
Allium lacunosum is a California species with small white to pale pink flowers in close umbels. It has four varieties. The first photo below is Allium lacunosum var. lacunosum grown by Nhu Nguyen. The second photo taken by Mary Sue Ittner is of an unknown variety.
Allium lemmonii is has a rather broad range in the western states. It is found on slopes made of mostly clay soil. It is a relative of Allium falcifolium where the leaves are flattened and somewhat falcate. The first photo shows the flower head, which is rather large, and the second photo shows the habit. Photos by Nhu Nguyen
Allium mannii - this is a Mexican species rare in cultivation. Surprisingly, many of the southwestern, Texan, and even Mexican onions are proving to be hardy in northern New England. This species is quite different than most other American onions, perhaps closed allied to A. plummerae from Arizona and New Mexico. Allium mannii has spread slowly via short rhizomes, and reliably puts forth upfacing "rounded star-cup" flowers in open clusters for several weeks in July. As the fresh white flowers mature, the central ovaries age from pink to orangish-brown. Photo by Mark McDonough.
Allium membranaceum grows in Northern California at moderate elevations and is similar to Allium campanulatum. It has white to pale pink flowers and a very dainty appearance. Photos by Mary Sue Ittner
Allium index – American alliums A-C – American alliums D-H - 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