The genus Allium contains approximately 850 species, and it is the "type" for the family Alliaceae, although once considered part of Liliaceae and Amaryllidaceae. The genus is perhaps best known from the handful of species that make up the edible food crops we're all familiar with, e.g. onions (Allium cepa), leeks (Allium ampeloprasum), garlic (Allium sativum), scallion (Allium fistulosum relative), and chives (Allium schoenoprasum); but many more species are known for their ornamental value and are thus dubbed the "ornamental onions". Alliums are hardy perennials, having true bulbs, or less-developed vestigial bulbs attached to rhizomes, the latter known as rhizomatous onions. Many species require a winter dormancy and chill whereas other species such as those occurring in a mediterranean climate require a dry summer dormancy. The center of Allium diversity is in the Mediterranean/Middle East region, eastern Asia and North America. In North America, the center of diversity lies in western Texas and the California Floristic Province. There are about a hundred species and varieties that occur in North America.
Allium was the subject of the Pacific Bulb Society's topic of the week in March 2003. Click on Introduction to read Mark McDonough's introduction and on Follow-ups from Mark to read some of his other contributions that week. One useful book for this genus is Davies, 1992 described in References.
Allium "Garden View" 1 - In July the allium garden is at its peak with numerous flowering species. In this view there's a drift of rosy-purple Allium cernuum in the background, an upright clump of A. plummerae with white flowers just starting to open, and in the foreground on the left, various forms of Allium flavum ssp. tauricum in pink and tan colors, with the drooping buds of Allium stellatum on the right (which are weeks away from bloom in late August). Allium "Garden View 2" - In mid July, among the searing heat in the upper 90's Fahrenheit (36 Celsius), the allium garden is a simmering landscape of pastel flower sprays and color bobs wavering in the hot breeze. The last photo shows bulb profiles - Bulb Profiles - a view of four uprooted allium species with the soil washed off. From left to right the species are: A. przewalskianum (an Asian species; notice the orange bulb coats), A. heldreichii (a hardy species from Greece), A. amplectens (pink form of this western American onion), and Allium schoenoprasum 'Snowcap' on the right, a dwarf white-flowered chive. Photos by Mark McDonough.
Representatives of some of the species are shown below.
Information on named species can be found on the wiki pages below or by clicking on the name of the species in the table.
Allium flavum Relatives – Allium hybrids – American alliums A-C – American alliums D-H – 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
For more information on the huge and varied genus Allium, please visit Mark McDonough's website
Allium flavum Relatives – Allium hybrids – American alliums A-C – American alliums D-H – 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