Doug Mandel
Apr 17, 2025
American Valley Sulphur Flower, Eriogonum umbellatum var. dumosum
April 2025 Plant of the Month
Assets: Summer color and high wildlife value.
This hardy variety of sulphur buckwheat has one of the most exceptional flower shows among the California flora. The sulfur-yellow flowers appear from spring into summer in a profusion of compact clusters a few inches above a mounding bed of gray-green leaves. The flower fades from yellow to an appealing rusty orange during the summer.
This small, summer semi-deciduous shrub measures 1 – 2 feet tall and 1 – 3 feet wide. Plant in full sun to part shade in companionship with other climate-adapted shrubs and perennials. It does best in well-drained soil and would work great on steep slopes and banks, on mounds, in rock gardens, and along borders.
It is native to the woodlands and forests of the Klamath, Cascade, and inner North Coast Ranges and the northern Sierra Nevada but has adapted well to Redding’s intense summer heat without needing much summer supplemental irrigation once established. One of our home sulphur buckwheats reseeded to a rock slope with little soil or supplemental water. By the end of summer, it looks a bit sparse but surprisingly good. The sulphur buckwheats in our more resource intensive formal gardens produce denser foliage and many more flowers. I find that assisting Nature is more wonderous than imposing my unexceptional will.
The nectar provides fuel for the butterfly, moth, and bee pollinators. The leaves are a larval food source for several species of Lepidoptera, and the seeds help sustain seed-eating birds during late summer, fall. The seed heads also provide some shade during the summer months. Deer do not normally browse the foliage, but they may nibble the flowers. We have a family or two of deer, and they have left these plants alone, so far.
Thoughtful maintenance is key to a successful garden, especially a native plant garden. Deadheading buckwheats is tedious, removes an interesting aspect of the plant structure, and pulls food out of the food web. If desired, however, prune dried seed heads in late summer and into fall. Since buckwheats flower on new wood, the hard pruning should be done in winter before the flush of new growth. Older plants needing rejuvenation can be cut back into older wood.
HAPPY Gardening!
