Herbs, erect, 1-8 dm, thinly tomentose to floccose, whitish to grayish or brownish to reddish brown. Stems: aerial flowering stems erect, 0.5-3 dm, thinly tomentose to floccose. Leaves basal and cauline; basal: petiole 1-4 cm, thinly tomentose to floccose, blade oblanceolate to narrowly oblong, 1-3(-5) × (0.3-)0.5-1(-2) cm, tomentose on both surfaces, sometimes merely floccose and grayish or brownish to reddish brown adaxially; cauline: petiole 0.3-1.5(-2) cm, mostly floccose, blade elliptic, 0.5-3 × 0.3-1 cm, mostly tomentose and whitish to grayish. Inflorescences cymose, often distally uniparous due to suppression of secondary branches, open, 10-70 × 10-45 cm; branches straight or nearly so, infrequently inwardly curved distally, thinly tomentose to floccose; bracts 1-3 × 1-3 mm. Peduncles absent. Involucres appressed to branches, cylindric, (3.5-)4-5 × 2-3 mm; teeth 5, erect, 0.2-0.4 mm. Flowers 1.5-2(-2.5) mm; perianth white to pink or red, occasionally yellow, glabrous; tepals monomorphic, narrowly obovate to oblong; stamens included, 1-1.5 mm; filaments pilose proximally. Achenes brown, 3-gonous, 1.8-2(-2.2) mm. 2n = 18. Flowering May-Nov. Sandy and gravelly flats and slopes, mixed grassland, chaparral, and sagebrush communities, oak and pine woodlands; 0-2200 m; Calif., Oreg.; Mexico (Baja California). Eriogonum roseum is widespread and typically common; occasionally it will be locally abundant but only rarely can it be considered weedy. It occurs from southwestern Oregon south through much of California to northern Baja California Norte, Mexico. Morphologically this annual species approaches the perennial E. elongatum, and poorly prepared specimens sometimes are difficult to differentiate. A clear distinction between E. roseum and E. gracile appears to be consistently possible in the field, but some herbarium material can be difficult to assign. By and large, E. roseum is more robust and less branched than the decidedly more slender and graceful E. gracile.
Seeds of Eriogonum roseum were pounded into a powder and either mixed with water and used as a beverage or eaten raw by the Kawaiisu people (M. L. Zigmond 1981).