Plants (30-)50-200 cm; caudices stout, woody. Stems 1(-5), erect, glabrous proximally to strigillose in arrays. Leaves: basal and proximal cauline (sometimes withering by flowering) tapering to winged petioles, blades lanceolate to ovate-elliptic, 50-300 (including petiole) × 12-80 mm (sometimes firm), margins sharply serrate to crenate or entire, faces glabrate to sparsely strigillose; mid to distal cauline sessile, blades narrowly ovate to lanceolate or elliptic, 25-90 × 5-30 mm, gradually reduced distally, margins serrulate to entire (distally), ciliate , faces glabrous or sparsely scabroso-strigose. Heads 15-300+ , not secund, in usually dense, sometimes open, elongate, paniculiform to thyrsiform arrays, (5-)10-45 × (2-)3-7(-12) cm; branches strongly ascending, often racemiform. Peduncles 1.5-3 mm, sparsely to moderately scabroso-strigillose; bracteoles linear, grading into phyllaries, scattered along peduncles, clustered near heads. Involucres narrowly campanulate, 4-6.5 mm. Phyllaries in 3-4 series, appressed, strongly unequal, outer ovate, mid and inner lanceolate, (midnerves often raised and thick) apices acute to obtuse or rounded, glabrous. Ray florets (2-)3-7(-9); laminae 3-4 × 0.5-1 mm. Disc florets 6-16; corollas 2.5-4 mm, lobes 0.5-1.2 mm. Cypselae (narrowly obconic) 1.6-2.5 mm, glabrous; pappi 3-4.5 mm. Solidago speciosa occurs scattered throughout its range, often in small populations. Five races have been acknowledged; only three varieties appear to warrant recognition. The species is divided into two nearly allopatric subspecies. The typical subspecies includes two varieties that are sometimes difficult to distinguish and considerably overlap in their ranges. The differences in size and number of leaves and persistence of the proximal cauline leaves may be caused in part by growing conditions.