Plants (20-)35-80(-100) cm; rhizomes woody, caudexlike. Stems 1-10+, usually blue to purple, glaucous, arching, straight , usually simple, occasionally with 2-3(-4) elongated lateral branches, glabrous or slightly strigose in arrays. Leaves: basal withering by flowering; proximal to mid cauline sessile, blades lanceolate, (47-)70-100(-150) × 8-20(-30) mm, margins serrate (with 0-24 teeth per side), apices acuminate, faces abaxially glabrous or sparsely hairy, adaxially sparsely hairy; distal sessile, blades narrowly lanceolate, (20-)40-70(-100) × (3.4-)5.6-11(-17) mm, margins entire to slightly serrate, faces glabrous or sparsely hairy. Heads 9-380, in short, secund, axillary and terminal racemo-paniculiform clusters (4.4-)13-36(-58) cm. Peduncles 2-10 mm, sparsely to moderately strigose; bracteoles linear, 1-8. Involucres narrowly campanulate, (3.5-)4.8-6(-7.2) mm. Phyllaries in ca. 3 series, unequal, outermost lanceolate (1-1.7 mm), acute, innermost linear-oblong (2.3-4 mm), 1-nerved, obtuse to acute. Ray florets 1-6; laminae (1.5-)2-3(-4) × ca. 1 mm. Disc florets 3-6(-9); corollas 2-3(-4) mm, lobes (0.5-)1-1.5(-2) mm. Cypselae 1-2(-2.5) mm, moderately to densely strigose; pappi 2-3(-3.7) mm. Solidago caesia is sometimes defined more broadly to include the erect-stemmed S. curtisii and S. ouachitensis.