Sulphur-flower buckwheat
Eriogonum umbellatum · Polygonaceae
The gardener's calendar
Ideal time to plant sulphur-flower buckwheat: set it out when the soil is neither frozen nor waterlogged, and water generously as it establishes.
ID card
- Family
- Polygonaceae
- Type
- Perennial herbaceous plant
- Flowering
- June to September, yellow flowers in umbels
- Adult size
- 20 to 40 cm in height
- Foliage
- Persistent, grayish-green
- Hardiness
- Hardy down to -15 °C
- Origin
- Western North America (United States)
- Soil type
- Well-drained, poor to moderately fertile
Care
Watering
Umbrella eriogonum prefers dry to moderate watering. Water moderately during the growing period, then reduce significantly once established. In winter, watering should be minimal, as the plant dreads stagnant moisture which promotes root rot.
Exposure
This plant requires a sunny exposure, ideally 6 to 8 hours of direct sunlight daily. In very hot climates, light afternoon shade can be beneficial, but it remains generally sun-loving. Choose a location that is airy and open.
Soil and drainage
Use a very well-drained, light, and poor substrate. A mixture containing sand, gravel, or perlite is ideal. Absolutely avoid heavy, clay, or enriched soils, which promote root suffocation. A rocky or stony soil is perfectly suited.
Pruning and cleanup
Prune lightly after flowering to maintain a compact shape and encourage branching. Remove faded flowers to extend flowering. In late autumn, clean up dead or dried stems, but keep part of the structure for winter.
Fertilization
Umbrella eriogonum is frugal and requires only very light fertilization, if any at all. If you wish to enrich it, apply a very diluted, low-nitrogen fertilizer only at the beginning of spring. Excessive feeding promotes foliage at the expense of flowers.
Pests and diseases
This plant is generally robust against pests and diseases. The main risk remains root rot in case of excessive moisture. Regularly check drainage and aerate the soil. Few interventions are necessary under normal conditions.
Did you know?
Umbrella eriogonum, whose name means 'bearing wool' in Greek (erion = wool, gon = angle), fascinates botanists with its umbel inflorescence bearing small, vibrant yellow flowers that are highly attractive to pollinators. It is traditionally used by the indigenous peoples of the Rockies and California, and remains a prime choice for modern xeriscaping and rock gardens.
Where to buy it
Plant in spring or early autumn, avoiding spells of intense heat. Pick a plant with healthy foliage and roots that are not exposed. Best time: March, April, May, September.
Add this plant to my garden →Plants from the same family
- SorrelRumex acetosa
- Pink knotweedPersicaria capitata
- Mile-a-minute vineFallopia baldschuanica
- RhubarbRheum rhabarbarum
- Maidenhair vineMuehlenbeckia complexa
- Red bistortBistorta amplexicaulis
Tips generated and checked by Viridia — adapt them to your local climate.