Flowers of sphaeralcea angustifolia
are variable in color; they may be red, or light or dark pink, though orange is more usual. Flowers form in small clusters near the tops of the stems; they are borne on a short stalk, about equal in length to the green, lobed calyx. Petals are obovate in shape, overlapping, and often slightly wavy along the upper edges. The bases of the petals are white. The flower center contains a compact group of several dozen stamens, which have reddish filaments and orange-yellow anthers.
This species is one of the tallest in the genus, with upright stems reaching heights of eight feet or more. Leaves are long and narrow, quite thick, and usually unlobed, though sometimes with a pair of triangular lobes at the base. Leaves have a prominent midvein, and (usually) one or two pairs of angled side veins. Stems and leaves have an even, sparse covering of star-shaped hairs