Plants 40-120 cm; caudices branching, woody. Stems usually 1, erect, glabrous, sparsely hairy in arrays. Leaves: basal when present similar to proximal cauline; proximal cauline often withering by flowering, tapering (sometimes rather abruptly) to short, winged petioles, blades ovate-lanceolate, 60-100(-150) × 30-40(-50) mm, thin, margins coarsely serrate, apices acute, abaxial faces hirsute on main nerves, adaxial sparsely hirsute to somewhat scabrous; mid to distal cauline subsessile to sessile, blades lanceolate, 20-50 × 5-20 mm, gradually reduced distally, margins entire. Heads 20-150, secund, in open paniculiform arrays, proximal branches elongate and widely divergent, sometimes pyramidal-secund with proximal branches short and recurved-secund. Peduncles 1.7-2 mm, sparsely to moderately short hispido-strigose, bracteoles 2-7, ovate, grading into phyllaries. Involucres 3-4 mm. Phyllaries (16-18) in 2-3 series, unequal; outer ovate, acute, inner linear-lanceolate, obtuse to acute. Ray florets 3-6; laminae 1-2 × 0.5-1 mm. Disc florets 4-7; corollas 2.7-3 mm, lobes 0.5-1.1 mm. Cypselae 1-1.6 mm, finely hairy; pappi ± 2.5 mm. Solidago helleri is possibly a hybrid of S. ulmifolia with S. delicatula.