The simple leaves of Hermannia aspera are nearly sessile to variably stalked. The leaves are alternate or a few may grow at each node, differing in size. A pair of leaf-like stipules is present, broad and rounded, narrowing into acutely pointed tips. Stipules are from less than 2 mm to 7 mm long.

The leaf-shape is variable, the lanceolate or oblong leaves may also be oblanceolate or ovate, the bases wedge-shaped and the tips lobed or notched. The brightly pale green to dark green blades are soft and coarse, appearing quilted, due to the ascending veins and midrib being sunken on the upper surfaces. The lower leaf surfaces are white with fine hairs, the upper ones sparsely hairy, some of the hairs tubercle-based. The leaf margins are rolled under and toothed, the teeth big and angular. Leaf dimensions are 5 mm to 30 mm long by 1 mm to 20 mm wide.

The young bud in picture is pointed with green calyx, its yellow corolla tip newly appeared. The old flower, now angled up on its straight, rigid pedicel, has an orange, faded corolla and a whitish calyx with centrally keeled, brown-ridged lobe midribs.

Upper, young branchlets are thickish and rough, variably covered in tubercle-based bristles (Bond and Goldblatt, 1984; iNaturalist; https://casabio.org; www.worldfloraonline.org).