Does it need fertilizer?

No, it prefers poor, rocky soil and will suffer if overfed.

How often should I water it?

Once established, it needs very little supplemental water.

Plant guide

Sulphur-flower buckwheat.

Eriogonum umbellatum

Pronounced eh-ree-OG-oh-num um-bell-AY-tum

Also known as sulfur buckwheat, sulfur eriogonum, sulfur-buckwheat, sulphur buckwheat, sulphur flower, sulphur flower buckwheat, sulphur wildbuckwheat, sulphur-flower

This hardy perennial is a fantastic choice for rock gardens and native landscapes. It produces vibrant clusters of yellow flowers that brighten up any sunny spot. You will love how it attracts pollinators throughout the summer months.

At a glance

Care level: Easy
Plant type: Perennial shrub
Light: Full sun
Indoor light: Direct sun
Water: Every 7 to 14 days
Mature size: 1 to 2 feet
Growth rate: Medium
Hardiness: USDA 3 to 8
Bloom time: Late spring to mid summer

Care

Plant this beauty in well draining soil to prevent root rot. Keep an eye out for mushy stems, which indicate the soil is staying too wet. It thrives with minimal attention once established in your garden.

Watering: Water deeply but infrequently, allowing the soil to dry out completely between sessions.
Feeding: This plant rarely needs fertilizer, but a light application of compost in spring can help.
Pruning: Trim back spent flower stalks in late autumn to keep the plant looking tidy.
Repotting: Only repot if the plant has outgrown its container or the soil has become depleted.
Soil: Sandy or rocky
Soil pH: Neutral to slightly acidic
Temperature: -30 to 35°C
Humidity: 10 to 40%
Drought tolerance: High
Lifespan: Perennial, typically 10 plus years.
Deer and rabbits: High

Signs it needs repotting

Roots growing out of the drainage holes.
Water sitting on the surface for too long.
The plant looks stunted despite good light.

Safety

People: There are no known reports of human toxicity for this species.
Children: The plant is generally safe, but its dry, brittle stems can be sharp for small children.
Contact allergens: The foliage can be slightly abrasive to sensitive skin.
Airborne allergens: The pollen may cause mild reactions in sensitive individuals during peak bloom.
Edibility: The plant is not considered edible for humans.

How to identify it

Clusters of bright yellow flowers
Small spoon shaped green leaves
White woolly undersides on leaves
Low growing mat forming habit

Height: 0.15 to 0.45m
Spread: 0.3 to 0.9m
Leaves: green, gray-green, evergreen
Flowers: yellow, cream, 0.5 to 1cm
Fruit: brown, Late summer

Problems to watch for

Root rot · This occurs when the soil remains too wet or poorly drained.

By symptom

Plant problems by symptom

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Growing it

Propagation: seed, cuttings
When to plant: spring, fall
Overwintering: Leave the foliage intact through the winter as it provides protection for the crown. Ensure the soil remains dry during the dormant season to prevent rot.
In containers: It grows well in containers if you use a very gritty, fast draining soil mix and a pot with excellent drainage.

Seed

Collect seeds in late summer when they turn brown.
Sow seeds in a gritty, well draining medium in autumn.
Keep the soil barely moist until germination in spring.

Group this plant with other drought tolerant natives to ensure they all thrive on the same low water schedule.

Grows well with

Penstemon · They share similar requirements for dry, sunny conditions.
Blue Grama Grass · This grass provides a nice textural contrast to the low mats of the buckwheat.

Similar species

California Buckwheat · It is a related species that also serves as a vital pollinator plant.

Science

Family: Polygonaceae
Genus: Eriogonum
Order: Caryophyllales
Class: Magnoliopsida
Native range: Western North America, from the Rocky Mountains to the Pacific Coast.
Conservation: It is not currently listed as endangered or threatened in the wild.

It survives by developing a deep taproot that accesses moisture in rocky, well drained mountain soils.

Value to wildlife: nectar source, larval host plant
Pollinators: bees, butterflies, moths
Uses: rock gardens, xeriscaping, pollinator gardens, ground cover

Through the year

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Flowering

Fruiting

Foliage

Ecological indicators

Salinity: 2/9
Soil reaction: 6/9
Light: 8/9
Temperature: 4/9
Moisture: 2/9
Nutrients: 2/9

Taxonomy resolved against GBIF.

Questions people ask

Does it need fertilizer?: No, it prefers poor, rocky soil and will suffer if overfed.
How often should I water it?: Once established, it needs very little supplemental water.

Where the name comes from

Eriogonum comes from the Greek words for wool and knee, referring to the hairy joints of some species. Umbellatum refers to the umbrella like shape of the flower clusters.

Good to know

It is commonly known as sulfur flower because of its bright yellow blooms.
It thrives in harsh, rocky soils where few other plants can grow.
The flowers often turn a rusty orange or red as they age.

Also in

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This guide was generated with AI on October 19, 2026 and checked against GBIF taxonomy. It is general information, not horticultural or veterinary advice. Read about how we build these guides.