Colorado Native Plant Feature - Sulphur Flower (Buckwheat)
Eriogonum umbellatum 'Kannah Creek' in a non-irrigated landscape
Common name: Sulphur Flower, Buckwheat, Sulphur Buckwheat
Botanical name: Eriogonum umbellatum
Mature height: 4” mat; up to 12+” with flowers
Mature width: 18-24”
Plant type: Woody evergreen perennial
Availability: Available from most nurseries, Plant Select 2007 winner
Bloom season: Late spring - summer
Bloom color: Red buds, yellow/chartreuse flowers, and seed heads that mature to various shades of bronze and coppery reds.
Hardiness zones: 3-8
Soil type: Prefers sandy and/or rocky soil, will grow in clay with proper amendments. Prefers neutral soils, but tolerates mildly alkaline or mildly acidic soils. Tolerates a fair range of soil PH ranges (5-7.5). Will grow in clay if infrequently irrigated until established and soil amended with structural amendments for drainage—best if it is neglected after establishment.
Water usage: Very low once established (~2 full seasons)
Sun exposure: Full sun to part shade
Native range: Western and Southwestern US, extending into western Canada
Wildlife value: High. Buckwheat provides a food source in either leaf or seed form to numerous fauna, including birds and mountain sheep. Highly valuable to bees, as they produce a particular honey that is darken and richer in color from the nectar. Bee species from the American bumblebee, sweat bee, and honey bee all benefit greatly from the flowers. A larval host and nectar plant for several species of native Colorado butterfly species. Also attracts beneficial insects to the landscape that mitigate infestation from aphids and other pests.
Landscape value: High value in xeric and native plantings. A woody perennial that forms evergreen mats of interesting texture and various leaf shades based on season. Requires little to no irrigation once established, and has 4 season interest. This plant will thrive where others struggle to get established, such as fast draining sandy and/or rocky soils. A great native, evergreen groundcover alternative to overused non-native plants of similar habit.
Description: Sulphur Flower is native to Colorado, from 700 feet to over 10,000 ft. It can be seen growing with other native, dry landscape plants such as lupines argenteus and various penstemons. It can be seen from far away when occurring in masses due to the color of the flowers. Typically found in dry, open, sunny slopes with shallower fast-draining soils. It prefers lean soils and infrequent irrigation, and can develop root rot in heavy, poor draining or overwatered landscapes. Does best in gravel mulch. The oval leaves are evergreen and unique, and in the winter will take on hues of purple and red, which starts in fall. The flowers emerge in spring on long stems, and have a dense cluster look of bright yellow that almost appears to glow. Through summer, the flowers age to various orange, red, and yellow shades. The plants will spread over two to three years and form a dense mat. An excellent plant for erosion control, habitat regeneration, and mass plantings. It is long-lived when planted correctly and virtually maintenance free (excepting removal of spent flowers in fall). The genus is one of the largest in the United States, rivaling Penstemons in number of various subspecies, which vary widely in habit and distribution. This plant won a 2007 Plant Select award, and should be considered for any commercial or residential landscape where an attractive, evergreen groundcover is desired.