Grewia rogersii is a compact spreading shrub, reaching up to 5 m high, with young branches initially covered in brown hairs that later become smooth, with purplish-brown bark. Leaves, measuring 70 x 37 mm, with a pointed or rounded tip, a rounded and sometimes asymmetric base, serrated edges, and a shiny dark green colour (bronze when dried), sparsely covered in tiny hairs on the upper surface and whitish or very pale brownish and tomentose underneath, with prominent veins. The petioles, up to 5 mm long, and stipules, up to 6 mm long, are both covered in whitish or brownish hairs. The inflorescences typically appear in the axils and usually bear 3 flowers each, with hairy peduncles and pedicels, while the bracts are not easily visible. The sepals, about 9 x 1.5 mm, are linear-oblong, hairy on the outside, and 3-nerved, but smooth on the inside. The yellow petals, roughly equal in length to the sepals, with a narrow, nectar-producing base, not wider than the blade base, and sparsely hairy on the inside. The androgynophore has a glabrous base and a slightly hairy apex but is not significantly extended beyond the glabrous base. The ovary is 4-lobed and densely hairy, while the style, measuring 3-5 mm long, is smooth, and the stigma lobes are broad. The fruit, when slightly immature, measures 9 mm in diameter, is deeply 4-lobed, and covered in short fuzz with longer brownish hairs. Flowering is in early summer, October to January.