Hibiscus clayi grows as shrubs or trees, reaching heights of 4 to 8 meters. The stems feature stellate pubescence at the apex but are otherwise glabrous. The leaves are simple and alternate, with narrowly elliptic blades to elliptic and occasionally oblong-elliptic to ovate or obovate, measuring 3 to 10 cm long and 1.5 to 5 cm in width. The apex of the leaves is acuminate or sometimes acute, with a cuneate or obtuse base. The upper surfaces of the leaves are glabrous, while the lower surfaces are glabrate, and the blades are green and shiny. The margins are entire or serrate towards the apex. The flowers are solitary and borne near the ends of the branches, with pedicels that are 1.5 to 2.5 cm long. The calyx is pale green, tubular to suburceolate, and the corolla consists of 5 petals that are abruptly flaring and dark red. The stamens form a monadelphous staminal column, which is exserted, with the filaments clustered below the apex of the staminal column. The fruit is a loculicidally dehiscent capsule, pale brown, oblong-obovoid, and enclosed by the calyx, measuring 1.2 to 1.4 cm long and puberulent. The seeds are brownish obovoid–obovoid-reniform, 4–4.5 mm long, sparsely pubescent with stellate simple hairs, with or without endosperm. It is native to dry forests and is found at elevations ranging from 230-350 meters.