I feel in general that the Buckwheats (Eriogonum) are woefully underutilized both ornamentally and as important plants for providing habitat in the garden. As ornamental perennials/subshrubs (small woody plants), they are dependable garden plants in terms of cold hardiness, ease of cultivation and reliable blooming with flowers that turn into attractive seed heads. The flowers and seed heads will often color the plants for a long season from early summer into fall.
Everyone should be planting to provide habitat fort pollinators (butterflies, honey bees, bumble bees and other native bees, hummingbirds) as well as other insects and birds. Eriogonum are an essential bee plant as they are an outstanding nectar and pollen source for bees. Eriogonum is also an important genus for attracting beneficial insects to protect the garden from aphids and other injurious insects. I’m not an ornithologist, but I suspect their grain-like seeds are also eaten by many bird species.
The genus is very easy to grow as long as the plants are matched with a low fertility (“lean”), well drained soil. Rocky and sandy soils that are challenging for establish new plants are perfect for the Buckwheats.
Many perennial Buckwheats take at least two growing seasons to reach mature size. When happy, most are long lived.
They generally don’t need much supplemental irrigation once established even in arid climates. Mulching is best done with crushed gravel, pine needles, crushed nut shells and other very course textured materials; no compost, shredded leaves or other moisture retentive mulches. I fertilize lightly once in the fall scratching in a dry organic type that contains alfalfa meal, kelp meal, rock phosphate and trace minerals (“rock dust”).
My favorites include for general use in xeriscapes for the Western US;
Eriogonum umbellatum v. ‘Kanah Creek’ (Plant Select introduction); growing from a seed collection made in western Colorado, ‘Kanah Creek’ is a large growing selection with a huge yellow umbels that age to various shades of bronzy orange in the late summer/early fall. Mature plants will become small shrubs. Great for beginners. Dwarf conifers like Mugo pine and wildflowers like Penstemon and native Salvia are excellent companion plants
Eriogonum corymbosum ‘Henrieville Yellow’
Only recently brought into cultivation, this new cultivar promises to be a great overall xeric native. Normally this species has a big cloud of white to pinkish flowers held over the foliage on wiry stems. ‘Henrieville Yellow’ was collected and brought into cultivation by UT native plant expert Dr. Susan Meyer who found a yellow flowered colony growing near Henrieville, UT. Blooming in late spring/early summer it stays in color all summer looking like a very showy yellow flowered Statice (Limonium). It has proven to be very easy to grow, is tolerant of modest irrigation and works very well in residential and commercial xeric plantings.
For rock gardens:
Eriogonum umbellatum v. porteri
A sub-alpine variety found primarily in the Tushar mountains of central Utah. This is a choice variety coveted by rock gardeners for its compact mat of evergreen leaves and dazzling display of brilliant yellow flowers aging into bright shades of orange and scarlet as the seed mature.