Buckwheats are members of the Eriogonum genus of the knotweed family. The largest and one of the most commonly grown of California buckwheats is St. Catherine's lace, which grows up to five feet tall and six feet wide and is native along the coast from Santa Clara County southward, but is recommended by the U.C. Davis Arboretum for gardens throughout the Sacramento Valley. Many of the other buckwheats are native to the Yuba-Sutter area. One of these is a shrub (having woody stems), one is a perennial forb (having soft stems), and the others are annuals (living only one year).
Buckwheats are the larval host plants for various butterflies, including the local Mormon metalmark, gorgon copper, blue copper, and Acmon blue. Additionally, the nectar of buckwheat flowers is a favorite drink for the adults of these species, as well as for the local Great Basin wood nymph, Western branded skipper, and American lady butterflies.
Shrub
Naked Buckwheat
Naked buckwheat is a three-foot-tall by three-foot-wide, white-, pink-, or yellow-flowering shrub that is native to Yuba and Sutter Counties and typically grows at elevations below 12,500 feet. It is most often found in dry areas in central oak woodland, valley grassland, or yellow pine forest. The Nisenan people used the hollow flower stems as drinking straws and pipes for smoking. They also ate the young stems, which taste sour.1 Naked buckwheat is the larval host plant for the local gorgon copper butterfly.
You can read more about it at the Theodore Payne Wiki and the Las Pilitas Nursery website. You can see pictures of it at CalPhotos, Flickr, and Picasa. You can find out where to buy it at the California Native Plant Link Exchange.
Perennial
Roundhead Buckwheat
Roundhead buckwheat (also called rock buckwheat) is a one-foot-tall, yellow- or orange-flowering perennial forb that is native to Yuba County and typically grows at elevations below 7,500 feet. It is found in yellow pine forest. It prefers full sun.
You can read more about it at USDA Conservation Plant Characteristics. You can see pictures of it at CalPhotos, Flickr, and Picasa. You can find out where to buy it at the California Native Plant Link Exchange.
Annuals
Wand Buckwheat
Wand buckwheat is a pink-, yellow-, or white-flowering annual that is native to Sutter County and typically grows at elevations below 6,000 feet. It is found in central oak woodland and yellow pine forest.
You can see pictures of it at CalPhotos, Flickr, and Picasa. You can find out where to buy it at the California Native Plant Link Exchange.
Goldencarpet Buckwheat
Goldencarpet buckwheat is a pink-flowering annual that is native to Sutter County and typically grows at elevations below 8,000 feet.
You can see pictures of it at CalPhotos, Flickr, and Picasa. You can find out where to buy it at the California Native Plant Link Exchange.
Wickerstem Buckwheat
Wickerstem buckwheat is a pink-flowering annual that is native to Sutter County and typically grows on the Sutter Buttes at elevations between 1,500 and 8,000 feet. It tolerates serpentine.
You can see pictures of it at CalPhotos, Flickr, and Picasa. You can find out where to buy it at the California Native Plant Link Exchange.
Footnotes
1. Wildflowers of Nevada and Placer Counties by the California Native Plant Society Redbud Chapter. Sacramento: CNPS Press, 2007