Batten Blooms
PL. —Eriogonum umbellatumBotanical illustration — drop image
Eriogonum umbellatum

Sulphur Buckwheat

SpringSummerFall
4a–8bHardiness zone
Peak bloom windowZone 6b · frost-offset weeks
Winter
Not in bloom
Spring
Not in bloom
Summer
In bloom
Fall
Peak bloom
Peak bloom
In bloom
Background

Sulphur buckwheat is a native perennial subshrub found across western North America from the Sierra Nevada and Cascade ranges east through the Rocky Mountains. It forms low, spreading mats of woody stems with small spoon-shaped leaves and produces dense, umbrella-like clusters of sulphur-yellow flowers on upright stems in late spring and early summer. It is widely used in xeriscape and native plant gardens for its drought tolerance, long season of interest, and low maintenance once established.

This plant is native to open, rocky slopes, sagebrush flats, and montane meadows, and it performs best when those conditions are replicated in the garden. It requires lean, sharply drained soil and declines quickly in clay or consistently wet conditions. Avoid organic mulch against the crown; a gravel or decomposed granite top-dressing keeps moisture away from the woody base and discourages rot. Established plants spread slowly by woody crowns and are long-lived with essentially no supplemental irrigation.

Sulphur buckwheat is an important larval host plant for several native Lycaenidae butterflies, including the lupine blue. It is also a significant nectar source for native bees, beetles, and wasps. Various Great Basin and Intermountain tribes used Eriogonum species, including this one, to treat headaches and stomach complaints.

Good companions
BlanketflowerBlue FlaxLittle BluestemYarrowCalifornia PoppiesPenstemonsCoyote MintsYarrows
Care guide
SunFull sun
WaterLow
SoilWell-drained, sandy or rocky, lean
Spacing18–36 in
Height6–18 in
Zone4a – 8b
Native RegionAZ, CA, CO, ID, MT, NV, NM, OR, UT, WA, WY
Direct sowFrost hardy
Seasonal tasks
winter
sowCold-stratify seed for 4–6 weeks in a moist paper towel in the refrigerator, then sow indoors at 65–70°F. Germination is slow and uneven; expect 3–6 weeks.
spring
watchInspect crowns during wet spring weather for early signs of crown rot or Phytophthora. Remove any mushy or blackened tissue and improve drainage if needed.
sowTransplant cold-stratified seedlings into individual deep pots to develop the taproot; harden off and plant out after last frost into prepared, sharply drained soil.
summer
watchCheck foliage in humid summers for powdery mildew, particularly on plants with poor air circulation. Thin surrounding growth if mildew appears.
fall
cutAfter the main flush of flowers fades, shear spent stems back to just above the foliage mat. Do not cut into the woody crown.
sowDirect sow seed outdoors in fall into a gritty, well-drained seedbed to allow natural cold stratification over winter.
Common problems

Crown Rot

Symptoms

Lower leaves yellow and wilt; the base of the rosette turns brown and soft, sometimes with white fungal threads at the soil line. Plants collapse in wet conditions.

Treatment

Remove and destroy affected plants. Improve drainage and avoid overhead watering. Do not mulch directly against the crown. Space plants for airflow and avoid replanting in the same wet spot.

Phytophthora Root Rot

Symptoms

Wilting despite moist soil, yellowing leaves, stunted growth, and dark, decayed roots and crown tissue. Vines may collapse during hot weather.

Treatment

Plant in well-draining soil and avoid waterlogging. Remove and destroy affected vines. Improve drainage with raised beds or amended soil and avoid overwatering.

Powdery mildew

Symptoms

White or grey powdery coating on leaves — usually starting on older growth in humid conditions or when nights cool.

Treatment

Improve air circulation by thinning plants. Apply neem oil or potassium bicarbonate spray at first sign. Avoid overhead watering.