Eriogonum

( err - ee - OG - on - um )

At-A-Glance Information

Also called Wild Buckwheat, this shrubby perennial grows best in full sun with little to moderate water. The flowers on this bush attract bees and butterflies and the seeds attract birds. Blooms last for a long season and generally fade to shades of tan, brown, and copper. Native to the California Coast, these plants have flowers that last a long time as cut flowers in water and can also be used in dried arrangements. These small shrubs are great choices for a rock garden.

Eriogonum Species and Varietals

The genus Eriogonum includes about 125 species and is a member of the family Polygonaceae. The genus name Eriogonum is derived from the Greek words for wool ('erion') and knee or joint ('gonu'), a name given to this group of plants by French botanist Andre Michaux in reference to the bent nature of the flower stems and the wooly feeling of the foliage. The best growing zones for Eriogonum depend on the species; see the descriptions below for more information. To find your zone, click here: Zone Map.

Eriogonum arborescens (Santa Cruz Island Buckwheat, Santa Cruz Island Wild Buckwheat)
This species grows best in USDA hardiness zones 7-11 or Sunset growing zones 5, 7-9 and 14-24. This shrub is native to Santa Cruz, Santa Rosa and the Anacapa Islands in southern California. Individual plants reach up to 3 to 4 feet tall and 4 to 5 feet wide. Bark is shredded and greyish-red. Grey leaves cluster at the end of branches, and groups of pale rose pink flowers appear at the end of spring through summer. This species is considered invasive on the California mainland.

Eriogonum cinereum (Ashyleaf Buckwheat, Coastal Buckwheat, Coastal Wild Buckwheat)
Grows best in USDA hardiness zones 7-10 or Sunset growing zones 5, 14-17 and 19-24. Individual plants reach up to 2-5 feet tall and 3 feet wide at maturity. Leaves are ash-colored and flowers are pale pink and form in ball-shaped clusters in summer. This species is native to the coast and canyons of southern California.

Eriogonum crocatum (Saffron Buckwheat, Conejo Buckwheat)
This shrub grows best in USDA hardiness zones 8-10 and Sunset growing zones 14-24 and is native to southern California. This is a more compact plant than others in the genus, getting to 1.5 feet and 2 feet wide. It produces white wooly leaves and yellow flowers in clusters appear in early spring to late summer.

Eriogonum fasciculatum (California Buckwheat, Flat-Topped Buckwheat, Eastern Mojave Buckwheat)
Native to the foothills of California, this species forms a clump 1 to 3 feet tall and 4 feet wide. Dark green leaves are wooly and white underneath. The species grows best in USDA hardiness zones 7-11 or Sunset growing zones 7-9 and 12-24. Pink or white flowers appear late spring to early fall. Great for erosion control. Varieties include 'Theodore Payne' (lower-growing) and 'Warriner Lytle' (makes an attractive groundcover).

Eriogonum giganteum (Saint Catherine's Lace, Giant Buckwheat, St. Catherine's Lace)
Grows best in USDA hardiness zones 8-11 or Sunset growing zones 5, 7-9 and 14-24. This shrub is native to the Santa Catalina and San Clemente Islands in Southern California. It can reach between 1.5 and 6 feet tall and 4-10 feet wide, making it one of the largest species in the genus. Plants have a free-branching habit with greyish white leaves and a long blooming period.

Eriogonum umbellatum (Sulfur Flower, Sulfur-Flower Buckwheat, Umbrella Plant, Sulphur Buckwheat)
This species grows best in USDA hardiness zones 3-10 or Sunset growing zones 1-24, Leaves are green above and white felted underneath. Blooms pop in late spring to early summer with yellow flowers that age to a rust color. Varieties include 'Shasta Sulfur' (low, silvery green mound with yellow flowers), 'Sierra' (forms a low dome with bright yellow flower clusters), and Eriogonum umbellatum aureum (or Kannah Creek Sulphur Buckwheat, with bright yellow flowers that age to an orange/rust color).

Eriogonum wrightii (Wright's Buckwheat)
Grows best in USDA hardiness zones 4-9 or Sunset growing zones 7-11 and 14-24. Wand-like stems on this shrub form a mound 1.5 feet tall and 2 feet wide. Silvery green felted leaves and tiny white to pink flowers form in clusters along stalks in summer through fall.

Caring for eriogonum

Plant Eriogonum, or Buckwheat, in a space in the landscape that receives full sun; ideally, they appreciate between 6 and 8 hours of sun each day for the best blooms. When these flowers are grown in less light, they will not flower as profusely. Ensure that soil is well-draining, rich in nutrients, and has a pH of between 6.0 and 7.0 (slightly acidic to neutral). If local soils are particularly poor in nutrients or do not drain well, make sure to amend the planting area with plenty of organic compost before installing. Apply a layer of mulch around the planting area to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. Water new plantings regularly as they establish a strong root system in their new home. At maturity, these plants are considered drought-tolerant, able to get by on rainwater alone for most of the year with supplemental waterings during extended periods of drought. Take care to not keep the soil too moist, as this will create issues with root rot.

Fertilize yearly in early springtime with an application of 2 inches of compost around the base of plants. Pull mulch back before applying, work the compost gently into the soil a bit, water it in, and then replace mulch. Pruning is simple; remove any damaged, diseased, or dead foliage at any time during the growing season, and remove spent flower spikes to neaten up the appearance of plants and encourage reblooms. These plants will freely re-seed in the garden, and removing spent flower heads will discourage their somewhat weedy nature. Cut back hard (to a few inches tall) every 2 years or so to control for shape and rejuvenate the plant. These flowers are perennials, surviving for 3 to 5 years on average in the landscape before needing to be replaced. Certain species in ideal growing conditions can reach up 18 to even 100 years old.

Propagation

Eriogonum can be propagated either by using cuttings or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the cutting method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your shrub, follow the instructions below:

Propagating Eriogonum by Cutting

Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. A good substrate for propagation of cuttings is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
In spring or early summertime, choose the plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more 6 inch portion(s) of the end of a non-blooming branch and strip the leaves off of the lower half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about four to six weeks have passed, your cutting should be rooted. When you notice new growth, you'll know you have roots.
Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant it to its new home. Ensure that the last frost of the year has occurred before doing this, as it can seriously damage your new plant.

Propagating Eriogonum by Seed

Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. The best potting medium for seed germination is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
Harvest your seeds in late August. Eriogonum seeds are contained inside of the dried flower heads on the plant. Cut them off of the plant, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. They will begin to split open and release the seeds contained inside. Once they have been released, take them out of the bag and put them in a container so you can work with them.
Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well.
Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.

Eriogonum seeds are contained in the dried flower heads of the shrub.

Eriogonum seeds.

Problems and Pests

Certain species are considered invasive in some regions; see the species descriptions above for more information. Check with local authorities before planting. Eriogonum shrubs are generally pest and disease free, though they can suffer from time to time from issues with the following: