''Eriogonum umbellatum'' is a species of wild buckwheat known by the common name sulphurflower buckwheat, or simply sulphur flower. It is native to western North America from
California
California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...
to
Colorado
Colorado (, other variants) is a state in the Mountain states, Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the wes ...
to central Canada, where it is abundant and found in many habitats, including the
sagebrush steppe
Sagebrush steppe is a type of shrub-steppe, a plant community characterized by the presence of shrubs, and usually dominated by sagebrush, any of several species in the genus '' Artemisia''. It is an extremely variable plant and hard to identify because individuals can look very different from one another. Also, there are many varieties. It may be a perennial herb blooming by summer with stems 10 centimeters tall and two to six clusters of flowers, with a whorl of leaves below the stems, or a sprawling shrub approaching two meters high and wide. The leaves are usually woolly and low on the plant, and the flowers come in many colors from white to bright yellow to purple.
It is a popular larval host, feeding the bramble hairstreak, desert green hairstreak, lupine blue, Mormon metalmark, Rocky Mountain dotted blue, Sheridan's hairstreak, Sonoran metalmark, and western green hairstreak. Additionally, goats and domestic sheep feed on the plant.
Varieties of this species include, but are not limited to:
*''E. u.'' var. ''argus'' - often nearly hairless leaves and bright yellow flowers; limited to the
Klamath Mountains
The Klamath Mountains are a rugged and lightly populated mountain range in northwestern California and southwestern Oregon in the western United States. As a mountain system within both the greater Pacific Coast Ranges and the California Coast ...
*''E. u.'' var. ''dichrocephalum'' - found throughout much of the western United States
*''E. u.'' var. ''furcosum'' - a low shrub native to the Sierra Nevada
*''E. u.'' var. ''glaberrimum'' - (green buckwheat) - a nearly hairless, white-flowered species
*''E. u.'' var. ''humistratum'' - (Mt. Eddy buckwheat) - a rare northern California
endemic
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...
*''E. u.'' var. ''juniporinum'' - (juniper buckwheat) - an uncommon plant of eastern California and western Nevada
*''E. u.'' var. ''subalpinum'' - (sulfur buckwheat) - similar to ''Eriogonum eriogonum'' but has wider and more spoon-shaped leaves
*''E. u.'' var. ''torreyanum'' - (Donner Pass buckwheat) - known from fewer than 10 occurrences near the
Donner Pass
Donner Pass is a mountain pass in the northern Sierra Nevada, above Donner Lake and Donner Memorial State Park about west of Truckee, California. Like the Sierra Nevada themselves, the pass has a steep approach from the east and a gradual appr ...
*''E. u.'' var. ''versicolor'' - bears pinkish-brown flowers with bright stripes
Cultivation
The wildflower gardening author Claude A. Barr complemented sulphurflower buckwheat as a "treasure in appearance and in adaptation in my garden." It is valued for its very low water usage for
xeriscaping
Xeriscaping is the process of landscaping, or gardening, that reduces or eliminates the need for irrigation. It is promoted in regions that do not have accessible, plentiful, or reliable supplies of fresh water and has gained acceptance in other ...
. The cultivar "Kannah Creek", a selection of ''Eriogonum umbellatum'' var. ''aureum'', has been introduced to the garden trade by the Plant Select cooperative sponsored by Colorado State University and Denver Botanic Gardens. It grows in USDA zones 4–8.
File:2016.06.01 19.22.47 DSC04649 - Flickr - andrey zharkikh.jpg, ''E. umbellatum'' var. ''dichrocephalum''
File:Eriogonum umbellatum humistratum 1.jpg, ''E. umbellatum'' var. ''humistratum'' (habit)
Image:Eriogonum umbellatum humistratum 2.jpg, ''E. umbellatum'' var. ''humistratum'' (flowers)
Image:Eriogonum_umbellatum_17015.JPG, ''E. umbellatum'' var. ''hypoleium'' (habit, William O. Douglas Wilderness)
Image:Eriogonum umbellatum 17009.JPG, ''E. umbellatum'' var. ''hypoleium'' (flowers)
File:Eriogonum_umbellatum_7298.JPG, ''E. umbellatum'' var. ''majus'' (flowers,
Wenatchee Mountains
The Wenatchee Mountains are a range of mountains in central Washington (state), Washington State, United States, United States of America. A major subrange of the Cascade Range, extending east from the Cascade crest, the Wenatchee Mountains sepa ...
)
File:Eriogonum_umbellatum_var_subaridum_1.jpg, ''E. umbellatum'' var. ''subaridum'' (flowers,
Spring Mountains
The Spring Mountains are a mountain range of Southern Nevada in the United States, running generally northwest–southeast along the west side of Las Vegas and south to the border with California. Most land in the mountains is owned by the Uni ...