Skip to main content
Eriogonum umbellatum (Sulfur Buckwheat)
1 / 10
© Claire Gentry, some rights reserved (CC-BY-NC) · iNaturalist

Eriogonum umbellatum

Sulfur Buckwheat

At a Glance

FoliageEvergreen
Height4-24 inches (10-60 cm)
Width12-36 inches (30-90 cm)
Maturity3 years

Growing Zones

USDA Hardiness Zones

3 - 8
These zones indicate the coldest temperatures this plant can typically survive.
What's my zone? →
Frost Tolerancehardy

Overview

Eriogonum umbellatum is a perennial subshrub forming low mats or mounds, reaching 4-24 inches (10-60 cm) tall in flower depending on variety and spreading 12-36 inches (30-90 cm) wide. Branches are woody at the base with terminal rosettes of evergreen leaves. Leaves are ovate to elliptic, 0.4-1.2 inches (1-3 cm) long, with green upper surfaces and densely white-woolly undersides. Erect leafless flowering stems hold compound umbels 4-16 inches (10-40 cm) above the foliage; a single involucre of leafy bracts subtends the umbel where rays branch. Individual flowers are sulfur-yellow at peak bloom, fading to orange or rust as they age, 0.1-0.2 inches (3-5 mm) across. Bloom occurs from June through August. Achenes are 3-angled, 0.1 inch (3 mm) long. Plants persist 10-20 years on well-drained sites; lifespan is shorter on heavy or irrigated soils. Foliage darkens to bronze or burgundy in autumn and remains on the plant through winter. The species includes more than 40 recognized varieties differing in height, leaf shape, and flower color depth.

Native Range

Native to western North America from southern British Columbia and Alberta south through California, Arizona, and New Mexico, and east to western Colorado and Wyoming. Found on rocky slopes, ridges, sagebrush steppe, montane meadows, and subalpine ridges at 1,000-12,000 feet (300-3,650 m) elevation, with varieties occupying distinct habitats.

Suggested Uses

Used in rock gardens, gravel gardens, and dryland meadow plantings at 18-30 inch (45-75 cm) spacing. Suited to xeriscape designs, scree beds, and pollinator restoration; flowers attract native solitary bees, small butterflies, and Mormon metalmark caterpillars. Performs poorly in mixed perennial borders with regular irrigation.

How to Identify

Distinguished from other Eriogonum species by sulfur-yellow flowers in compound umbels and a single involucre of leafy bracts where umbel rays branch. Differs from E. heracleoides (cream-yellow flowers, midstem leaf whorl) and E. strictum (variable flower color, no involucral bracts at the umbel branching point). Leaves are ovate to elliptic with white-woolly undersides, clustered in terminal rosettes on woody branches. Flower color shifts from sulfur-yellow to rust-orange as bloom progresses.

Appearance

Size & Dimensions

Height4" - 2'
Width/Spread1' - 3'

Reaches mature size in approximately 3 years

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~6 weeks
J
F
M
A
M
J
J
A
S
O
N
D
Flowers open from June through August across most of the range; peak bloom occurs in early July at mid-elevations and in late July to August at subalpine sites. Individual umbels remain in bloom 3-4 weeks; total floral display lasts 5-7 weeks per plant. Flowers fade from sulfur-yellow through orange to rust-brown as they age and persist on the plant through September. Higher-elevation varieties bloom 2-3 weeks later than valley populations.

Detailed Descriptions

Flower Description

sulfur-yellow, aging orange to rust-brown

Foliage Description

green with white-woolly undersides; bronze to burgundy in fall and winter

Growing Conditions

Sun Requirements

Requires 6-12 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range6.0 - 8.0(Neutral)
357912
Soil Types
Drainagewell drained

Water & Climate

Water Needs

Very Low

Frost Tolerance

hardy

Time to Maturity

2-3 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Water deeply weekly during the first growing season; established plants tolerate 6-8 weeks without rain in regions receiving at least 10 inches (25 cm) of annual precipitation. Plants in irrigated borders or clay soils develop crown rot and decline within 2-3 years. Aphids may colonize flower stems in early summer; populations typically remain below 30 individuals per stem. Plants self-sow modestly on bare gravel, producing 5-15 seedlings per parent annually. Fertilizer is not required; supplemental nitrogen produces lax stems and reduced flowering. Replace plants when crowns die out, typically after 10-20 years.

Pruning

Spent flowering stems are cut to the basal foliage in late summer once seed dispersal is complete. The persistent burgundy or bronze foliage remains intact through winter; dead leaves break off as new growth resumes in late April. Cuts into the woody crown can kill the plant; pruning is typically limited to the leafy zone above the woody base.

Pruning Schedule

J
F
M
A
M
J
J
A
S
O
N
D
summerfall

Maintenance Level

low

Container Growing

✓ Suitable for container growing

Minimum container size: 5 gallons

⚠️ Toxicity Warning

Non-toxic