Herbs, biennial, erect, gla-brous. Stems rootstocks, horizontal, simple, bearing basal rosettes (axillary shoots with subterranean, white stems that detach easily and bear terminal rosettes of colorless leaves). Leaves alternate, spreading, outermost ones petiolate (petiole 4-5 mm); blade green or greenish white, not glaucous, oblanceolate, obovate, or narrowly spatulate, laminar, 2-16 × 1.4-3.2 mm, base not spurred, not scarious, apex blunt, (surfaces papillose). Flowering shoots erect, simple, (5-)11(-18) cm; leaf blades ovate or elliptic, base not spurred; offsets not formed. Inflorescences cymes, 5-60-flowered, 3-6-branched; branches often strongly recurved, each 1 or 2 times dichotomously forked; bracts similar to leaves, smaller. Pedicels to 0.3 mm. Flowers (5-)6(-7)-merous; sepals erect, slightly connate basally, green, ovate, equal, 1.5-2 × 0.7-1.1 mm, apex acute; petals spreading, distinct nearly to base, canary yellow, keel green or dark red, lanceolate to oblong, carinate, 4-6 mm, apex subobtuse to acute; filaments yellow; anthers yellow; nectar scales deep yellow, subquadrate. Carpels stellately spreading in fruit, connate basally, brown. 2n = 16.

Flowering spring-summer. Open or largely bare areas, basalt or limestone, rocky hillsides, cliffs; 50-1200 m; Idaho, Oreg., Wash.

Variation in the number of floral parts of Sedum leibergii (5-7-merous) is unique in North American sedums. It has tiny rosettes of lax, long-spatulate basal leaves that mostly have shriveled by anthesis. Sedum borschii, which is often confused with S. leibergii, has primary rosettes, prominent at anthesis, that have obovate or elliptic leaves.