Submitted by gsparrow on Thu, 12/06/2018 - 12:49

My personal introduction to wild buckwheats was in 2005, the year I instigated a native plant domestication project at the University of Idaho’s Aberdeen Research and Extension Center. In the process of accumulating research materials, I collected seed of several buckwheat species in the mountains of central Idaho and established plants in evaluation plots on the research station where I work. “They’re awfully slow growing,”was my initial response as I inspected one-year-old sulphur-flower buckwheat plants in my evaluation plots. Following
a second year of growth – and the appearance of a few flowers – my
opinion improved markedly and I began to watch the plants closely.
By the end of the third growing season, my thoughts had evolved 
along the lines of: “How can anyone find satisfaction in life without cultivating at least one outstanding buckwheat.” Many times since, I have wondered why buckwheats continue to escape recognition within horticultural circles. I’m always pleased when knowledgeable NARGS members beat the drum for the buckwheats and so this article is written to provide some information and education about this intriguing group of plants.

 

Taxonomically, the wild buckwheats are characterized as species within the genus Eriogonum, one of the genera within the knotweed family (Polygonaceae). It is a large genus, containing over 250 distinct species. The genus Eriogonum is divided into 7 subgenera, based
on flower morphology, plant structure, growth habit, life cycle, and distribution. Geographically, species within the genus Eriogonum are restricted to North America (including Mexico) and are native primarily to the dry climes located in the western portion of the continent.

Species of Eriogonum with the greatest horticultural potential are long-lived perennials belonging to one of two subgenera – Eucycla (containing 110 species) and Oligogonum (containing 36 species). Both subgenera are comprised of plants with a range of stature and morphology. Subgenus Eucycla includes a number of the very best small bun species, although it also contains such large shrub species
as
Eriogonum corymbosum and E. fasciculatum. Subgenus Oligogonum is comprised largely of very attractive subshrubs, including species such as E. umbellatum. But this subgenus also includes short-statured cushion plants such as E. caespitosum and diminutive shrubs like E. thymoides.

The wild buckwheats are morphologically and physiologically diverse. Growth forms include shrubs, subshrubs, and non-woody (herbaceous) plants. Their life-cycles can be perennial, biennial, or annual. Some species grow taller than the average person; others are small enough to slip unnoticed beneath a hiker’s boot. Depending on climate, some species are evergreen, others deciduous. Flowers – all very tiny individually but often in clustered heads – may be white, yellow, pink, or red. Bloom time ranges from very early spring to very late fall. From a horticultural perspective, there is a buckwheat species to meet any objective in almost any garden.

Garden-Worthy Eriogonum Species

To date, I have had opportunity to grow and observe 56 species of wild buckwheats. I would like to share with you my impressions and observations as they relate to some of the best garden plants. As you read through the descriptions, recognize that my observations are influenced by personal circumstances. To put things into perspective, I live in the cold desert climate of southeastern Idaho; USDA hardiness zone 4, 106-day frost-free season, annual precipitation less than 10 inches, and soil pH of 8.4. The southwestern desert or coastal species of buckwheats do not survive my winters. On the other hand, with minimal supplemental irrigation, I can grow most of the hardy
species without the need to amend soils or improve drainage. If you live where climate and soil conditions are distinctly different, it goes
without saying that my observations may not reflect your past or future experiences with species of Eriogonum.

In order to simplify my summary of garden-worthy wild buckwheats, I have chosen to divide them into four groups, based on stature and form rather than on taxonomic group:

small cushion species;

large cushion species;

subshrubs;

shrubby species.

Small Cushion Buckwheats

I include in this category some of the best buckwheats for planting in troughs, rock gardens, and other small spaces. The small cushion plants have densely mounded foliage and, when mature and in bloom, are typically less than 6 inches tall and 12 inches wide. These are the “cute” plants.

Eriogonum caespitosum (mat buckwheat). My introduction to this species came during a hike into the rugged lava fields common to the southern segment of the Craters of the Moon National Monument in Idaho. The yellow color of early spring blooms quickly attracted me
to these tough, rock-hugging plants. In subsequent travels, I found mat buckwheat to be a variable and widely distributed species, with representation in all western US states (except Washington), the southern Rockies of Canada, and high-elevation sites of northern Mexico. Outstanding attributes of mat buckwheat are the fuzzy, gray 
to silver, evergreen leaves and the ground-hugging habit. The flowers are bunched into small pom-poms at the top of thin, unbranched stems. The stems are usually short; and indeed I have seen forms of this plant with flower stems so short that the blooms are entirely embedded in the foliage. Bloom is very early with first flowers appearing in late March or early April. Bloom color is primarily yellow, although flowers on the female plants (it is a dioecious species) usually change to dark maroon after pollination. Although the bloom period is fairly short, the foliage makes a valuable contribution to the garden throughout the year. I find mat buckwheat to be a very utilitarian and attractive species in my rock garden.


Eriogonum douglasii (Douglas buckwheat). I obtained my first seeds of Douglas buckwheat from the now defunct Rocky Mountain Rare Plants. The original collection site was the Blue Mountains of north- central Oregon. Native range for this species includes these same Blue Mountains, the eastern Cascade Range, and the eastern Sierra Nevada Mountains of the western US. This tough little plant produces tight mounds of silver or silver-green, very fuzzy leaves. Even in my tough climate, during winters without a protecting blanket of snow, the leaves usually remain evergreen. Round balls of capitate flower heads grow at the top of stiff, unbranched stems. The flowers are bright yellow and fade to red with age. In my Aberdeen garden, Douglas buckwheat will bloom for about 6 weeks during May and June. I have found this to be a very dependable, long-lived, and attractive garden plant.

Eriogonum gracilipes (White Mountain buckwheat). This little jewel is endemic to the White Mountains of California where I saw it on a field trip associated with an annual meeting of the fledgling Eriogonum Society. White Mountain buckwheat is a diminutive plant, only 3–4 inches tall in bloom and not much wider. Plants form tight cushions of blue-green, fuzzy leaves. Flowers are produced in dense pom-poms at the ends of curved, unbranched stems. Flower buds are red. Newly opened flowers are cream or yellow then fade to shades of red. One of the things I really like about this species is its tendency to bloom off and on for an extended season – May into October. White Mountain buckwheat is a marvelous little rock garden plant, but in my climate it can sometimes experience significant winter injury. This species may need a slightly warmer climate or a site with consistent snow cover to be at its best. I am still looking for an accession that consistently holds up to exposure and winter cold. In my latest accessions, I see evidence that I am making a little progress along this line.

Eriogonum ovalifolium (cushion or oval-leaf buckwheat). Cushion buckwheat is a beautiful species. My first sight of it was at an elevation of over 10,000 feet while hiking to Brockie Lake in central Idaho. After stumbling upon a carpet of these beautiful plants, I spent hours photographing the decumbent soft pink flowers that decorated cushions of silver leaves. I later keyed these plants to the variety depressum, one of 12 botanical varieties recognized within this variable species. In my opinion, all 12 varieties are garden-worthy, although some are more attractive than others. Spoon-shaped, silver or silver-green leaves are densely arranged in tight mounds up to 6 inches tall. Flowers are arranged as pom-poms at the end of unbranched stems. At one end of the spectrum, I have seen forms of cushion buckwheat with flower stems up to 15 inches tall and, at the other end, flowers completely embedded in the foliage. Expression of flower stem length appears to be related to habitat elevation and exposure. Flower color ranges from cream, to yellow, to pink, to dark red. In Aberdeen, bloom begins in May and lasts for about 6 weeks. This is an exceptional species with superior garden potential. I highly recommend cushion buckwheat, in any of its forms, and urge interested gardeners to sample the variety of this wonderful species.

Eriogonum shockleyi (Shockley’s buckwheat). Shockley’s buckwheat can be found in several western states. It always seems to grow in the harshest of sites, and looks good doing it. Native habitat includes desert locations in the central and southern Rocky Mountains of the US. Flowers of Shockley’s buckwheat lack bright color but plants make up for this deficiency with exceptional form. Leaves are greenish-gray, fuzzy, and arranged in very tight buns. The white pom-pom flowers grow on short stems and appear to float at the surface of the foliage. The plants are in continuous bloom from June into October. The plants grow very slowly and always retain their compact, contained shape. Shockley’s buckwheat makes a very nice rock garden plant.

In addition to those described above, there are several other small cushion species that may be worth considering, including Eriogonum bicolor, E. breedlovei (lacks hardiness in my climate), E. kennedyi (lacks hardiness in my climate), E. kingii, E. ochrocephalum, and E. rosense.

Large Cushion Buckwheats

The large cushion species have much the same form as their small cushion cousins. However, their size precludes use in troughs or small gardens and makes them more suitable for placement in large rock gardens, beds, or borders. Plants of some of these species can be quite large, achieving a height of over 15 inches and a spread that may exceed 3 feet.

Eriogonum arcuatum (Baker’s wild buckwheat or James’s buckwheat). The jury is still out on the taxonomic classification of Eriogonum arcuatum. It is sometimes given species status and other times accorded a place with the yellow-flowering forms of E. jamesii. Baker’s wild buckwheat comes from the Four Corners region of Utah, Arizona, Colorado, and New Mexico. Regardless of taxonomic uncertainty, this is a marvelous garden plant. The dense, mounding foliage consists of silver-green, spoon-shaped, fuzzy leaves. Large, capitate heads, also very fuzzy, hold numerous dark yellow flowers. The best form of the species is the one frequently recognized as the botanical variety xanthum. Plants of this variety produce flower heads on short, unbranched stems that hold the flowers just above the foliage, thereby retaining cushion form through blooming. Although the unique form makes this plant striking when out of flower, the 6 weeks of May- through-July bloom creates additional appeal. Although I try not to show obvious preference amongst the buckwheats, I think this is secretly one of my favorite species.


Eriogonum compositum (arrowleaf buckwheat). I was stunned by the beauty of arrowleaf buckwheat when I first came upon the species in the south end of Hell’s Canyon in Idaho. In addition to western Idaho, this species also grows in eastern Washington and Oregon, and northern California. Arrowleaf buckwheat is a unique plant and I was unsure as to where to place it within my utilization categories. Plants lack the tight mound form of the other large cushion plants but its herbaceous habit precludes categorization as a shrub or subshrub. The leaves are large, arrowhead-shaped, and form a loose mound. The dark yellow flowers (accessions from some locations have cream-colored flowers) are arranged in huge, highly branched umbels that achieve heights of up to 2 feet. In bloom, with flowers usually lasting 5 to 6 weeks in June and July, this plant is a show-stopper. After bloom, the leaves remain healthy and attractive for the remainder of the summer. In fall, some plants provide a nice show of red leaf color. This is an unrivaled garden plant where there is sufficient room to let it strut its stuff.
Eriogonum pauciflorum (fewflower buckwheat). I have yet to figure out how this species got its common name. Plants in the garden grow large and flower profusely. Fewflower buckwheat is a plant of the western Great Plains and Rocky Mountain foothills. The best form I have found for the garden is derived from the variety gnaphalodes, an accession I obtained from the Eriogonum Society seed exchange. It was originally collected from Weld County, Colorado. The dense, silver-green foliage eventually reaches dimensions of 6 inches tall and up to 5 feet wide. By late June, sparse flowering begins but the best show is delayed until September and October when the plants are covered with flowers. The white blooms are arranged in small round pom-poms and the short, unbranched stems hold the flower heads near the top of the foliage. This large plant needs space, but is definitely worth considering as a garden specimen.

Eriogonum strictum (Blue Mountain buckwheat). I have grown many forms of Blue Mountain buckwheat over the years, some with silver leaves, others with brown; some with yellow flowers, others with white; some with upright, sparsely branched flower umbels, others with radiating, highly branched umbels that create dense spheres of flowers. Unique forms of this species are indicative of origin and representative of numerous habitats located throughout western North America. The forms I have grown to like best are derived from subspecies proliferum, var. proliferum and are native to the northwestern US states and British Columbia. Plants of this variety have tight mounds of silver leaves and lacy umbels of white or pink flowers held high above the foliage. This variety of Blue Mountain buckwheat blooms late in the season, flowering for 12 weeks in July through October, and is a great plant for providing late-season interest in the garden. This species tends to frequently seed itself around the garden, a trait that could potentially be troublesome if the plants weren’t so beautiful.

A number of other large cushion species are worth consideration for planting in the garden. Among these are: Eriogonum brevicaule,
E. capistratum (could be considered as a small-cushion species), E. coloradense, and E. jamesii (both the cream-flowered variety jamesii and the yellow-flowered variety flavescens).

Subshrub Buckwheats

Eriogonum subshrubs, by definition, are plants of relatively small size (at least compared to other shrubs), have a perennial woody base, and often produce leafy or flowering stems above the base that last for a single season. Most of the subshrubs have evergreen or semi-evergreen leaves. Many make very nice garden plants. Here are a few that have impressed me.

Eriogonum thymoides (thyme-leaf buckwheat). Plants of thyme-leaf buckwheat are proof-positive that woody plants can be very small. This tiny plant is a resident of the driest, rockiest places in Idaho, Washington, and Oregon. During a recent trek to Gooding City of Rocks in central Idaho – prime E. thymoides habitat – the largest plants I observed were 4 inches tall and in full bloom. Although tiny, the plants are well-formed and highly branched. The leaves are tiny, needle-like, blue-green in color, and densely situated along the stems. The flower heads are a study in contrast, bright white cotton balls, lined and striped with scarlet. If you wish to grow this intriguing little species, patience is essential. I have plants in their third year of life this past summer that finally managed to produce their very first flowers. But, if you have the right dry rock-garden site for this species, it is worth the effort and the wait to get it to flowering age.


Eriogonum umbellatum (sulphur-flower buckwheat). You could populate a garden with just this one species and still provide plenty of diversity and season-long interest. Sulphur-flower buckwheat is an incredibly variable species, comprised of 26 botanical varieties with a wide range of native habitats, plant stature, architectural form, foliage appearance, flower color, bloom time, and adaptation. All members of the species share some things in common, including a woody basal branch structure, evergreen or semi-evergreen spoon-shaped leaves, and cream or yellow flowers arranged in simple or compound umbels. Most of the recognized varieties have garden potential, but a few are especially interesting due to expression of one or more unique characteristics. For example, variety ellipticum is a tall, yellow-flowered (fades red), late-flowering form of the species that provides color after most wildflower species are past bloom. Variety minus is one of the most unusual forms of the species with mat-forming, lime-green foliage, decumbent flower stems, and amazingly dark red flowers. Variety porteri is one of the most diminutive forms of the species – a great rock garden plant – growing only 3 inches tall, with repeated cycles of bloom, and light yellow flowers that fade to red. No matter your preference, you can find a plant to appreciate among the sulphur-flower buckwheats.

Eriogonum wrightii (bastardsage or Wright’s buckwheat). I acquired my first accession of bastardsage from Ron Ratko, owner of Northwest Native Seed. The seed originated from the San Bernardino Mountains in California. I assumed this native of southwestern US and northern Mexico deserts would not survive winters in Idaho. Surprisingly, this species did OK most winters and when it did suffer from the cold, it left enough seedlings to maintain itself in my rock garden. Bastardsage produces a flat mat of foliage with woody stems. The silver, oval leaves cover the highly branched plants. In mid-summer, flexible, wand-like flower stems emerge from the foliage. Much later in the fall, white or pink flowers begin to open and decorate the numerous supple stems. As the flowers age, they fade into shades of orange and red. This is a dependable plant for adding late-season color and interest to the garden. However, bastardsage is prolific from seed and will require efforts to identify and remove volunteers each spring.

A few other subshrub buckwheats may be worth considering for the garden, including Eriogonum heracleoides (most forms are rather plain, but occasionally a nice one can be found), E. lonchophyllum, E. niveum, E. racemosum, and many of the other varieties of E. umbellatum beyond those I describe above.

Shrubby Buckwheats

Shrubby species may produce small or large plants, may have dense or sparse form, and may produce flowers arranged in heads or solitary blooms arranged along stems. The one thing they do have in common is woody, perennial branches as a basis for plant structure. Many of the shrubby species are native to warm deserts or coastal regions and are not hardy in Idaho, but here are a few that can take the winters of Zone 4.

Eriogonum corymbosum (lacy buckwheat). I first saw lacy buckwheat along a road in the red rock country south of Kanab, Utah. Timing was late in the season and only skeletons remained of the summer’s growth, but that was enough to kindle my interest. I harvested a few seeds and took them back to Aberdeen, fully expecting lack of hardiness to put an end to this misadventure. As things turned out, the plants were fully hardy and intriguingly beautiful. The plants are true shrubs, do not die back in winter, and produce inconspicuous, deciduous leaves along the stems. Lacy buckwheat can be a little homely in the spring after the old flower stalks are removed. But by mid-summer new wiry inflorescence structures begin to form and the plants transform themselves into the distinctive domes that originally piqued my interest. Depending on provenance, the dense domes may be a diminutive 10 inches tall or exceed 4 feet. At season’s end, thousands of white or pink flowers appear and put on a show until well after frost. The form and structure of lacy buckwheat is retained throughout the winter and into the next spring. I can’t now imagine my xeric garden without this plant.

Eriogonum sphaerocephalum (rock buckwheat). The rock buckwheat is a small shrub, but still a shrub. It is a widely distributed species native to the westernmost states and provinces of the US and Canada. I have harvested seed from many forms of rock buckwheat in my home state of Idaho. Some forms are rather plain, with olive-green leaves and cream to buff flowers. Other forms are very attractive with silver leaves and bright yellow flowers. These last make the best garden plants. Flowers are present for about 7 weeks in May to July, but the plants are attractive all summer. In warmer climates, the plants are evergreen, but in my garden and research plots, the leaves tend to be damaged in the winter and can become deciduous. Regardless, spring recovery is quick as the plants prepare for the summer’s annual performance. I have found rock buckwheat to be a very nice garden species.

There are a few other shrubby species of buckwheat that come from habitats that make me think they can take the cold of my Idaho garden. One shrub I have yet evaluate but may prove to be hardy is Eriogonum clavellatum. It may also be possible to discover a cold-hardy accession of E. heermannii, although I have yet to find it.

Tips for Obtaining and Growing Buckwheats

I guess an article on buckwheats would not be complete without a few growing tips to help interested gardeners succeed with these remarkable plants. Occasionally, potted plants of a few species of buckwheat can be found in the specialty nursery trade. However, getting access to most species will require propagation from seed. Here are a few ideas for obtaining seed, producing seedlings, establishing plants in the garden, and providing conditions for long-term plant health.

Buckwheat seed can be collected from the wild, purchased from wildflower seed suppliers (such as Alplains, Southwestern Native Seeds, Western Native Seed, or others), or obtained through the NARGS or Eriogonum Society seed exchanges (access provided to members of the respective organization). Wild-collected seed is ready for harvest when the spent flowers feel dry to the touch (they may still appear fresh and colorful). The seeds can be separated from the dried perianths by rubbing the dried flowers between your hands and blowing away the chaff.

Typically, buckwheat seed displays fairly high rates of germination and seedlings emerge fairly quickly. Wild-collected seed harvested after a dry year or following periods of active insect predation, may not germinate very well. When it comes time to plant your buckwheats, I would suggest growing seedlings in controlled conditions rather than just scattering the seed in the garden. Buckwheat seeds tend to be a favorite food for birds, small mammals, and insects. It’s rare to see mature plants produced by direct seeding. As for seed pretreatment, information derived from research literature would suggest that seeds of many buckwheat species, especially those native to high elevation sites, need relatively long periods of stratification (cold, moist treatment). My experience indicates this is not accurate. I have found that species from cold climates may benefit from 2 or 3 weeks of cold stratification, while those from warm climates do not require any stratification. Seeds can be stratified either by putting them in a plastic bag containing moist potting mix and placing them in the refrigerator or by planting them in containers and placing them outside in early spring. Seed stratified in plastic bags can be planted in flats or pots after cold treatment.

After emergence, damping-off of young seedlings is the most common cause of failure. Proper water management (moist but not wet,) is the best tool for preventing damping-off. Young seedlings must be grown in full sun or with plenty of supplemental artificial light. When the seedlings have two or three leaves, they can be transplanted into larger pots. For pot culture, use some type of soilless potting mix. Most gardeners use a soilless mix with excellent drainage characteristics (plenty of sand and gravel), but I have found that the type of mix is less important than proper moisture management. Even a short period of water-saturated soils may result in the loss of potted Eriogonum plants.


Establishing Plants in the Garden

Because I live where buckwheats thrive, I don’t have to worry much about amending soil or creating contours for improving drainage. This will not be true in every case. If you live in a damper climate, realize that nearly all buckwheats are xeric species and ensuring survival may require significant extra work directed at creating a healthy environment. Prepare the site prior to producing seedlings, primarily with intent to improve drainage, if needed. Time your activities to reduce the time seedlings need to spend in a pot. Many buckwheat species struggle in pot culture. Make an attempt to transplant potted plants into the garden the same year the seedlings are grown. Once transplanted into the garden, the plants will require frequent watering during the first few weeks, at which time a slow weaning process can be initiated. Once buckwheats establish the deep root system that makes them drought tolerant (may take several months), irrigation can be significantly cut back or eliminated. There are large differences among buckwheat species with regard to tolerance to moist conditions. Be sure to study species habitat requirements to figure out which ones are most likely to succeed in your climate and situation. 

Conditions for Long-Term Health

Buckwheats are low-input plants. They prefer soils with low organic matter, limited amounts of fertilizer, and
low to moderate levels of irrigation. Along with good drainage, limiting inputs is the key to keeping most buckwheat plants healthy. In simple terms, don’t love them to death. If your garden includes weed barrier and mulch, take measures to ensure moisture is not
held around the plant crowns, especially during fall and spring. Cut large holes in plastic mulch around the plants to keep the plastic from retaining moisture next to the stems. Use gravel or other non-organic mulches, rather than composts or wood mulches, to help minimize moisture retention.

Obviously, I can cover only the most essential elements of buckwheat culture within the scope of this article. Recognize that there are many other important principles that may enhance success. Any information you can find on the topic of growing xeric plants should be applicable to buckwheats. But the main thing is to watch the plants themselves, understand their responses, and adjust management accordingly. The plants will tell you what they need.

If you have less interest in gardening and more interest in learning about some of our remarkable North American wildflowers, I hope I have sparked some interest our wild buckwheats. I have just scratched the surface and I am sure you will discover many sources of additional information. If gardening is your forte, I hope your plant palette includes a few buckwheat species. If not, understand that your life may be less than satisfying without opportunity to cultivate at least one representative from the genus Eriogonum. Grow a buckwheat; then tell your friends.

Additional Reading

Reveal, J. L., “Eriogonum in the Garden,” Rock Garden Quarterly vol. 65, no. 2, p. 106-165 (available on the NARGS website).