The simple leaves of Sida cordifolia subsp. cordifolia are alternate on long petioles (1,5 cm). The leaf-shape is ovate, the base rounded to shallowly lobed, the tip tapering acutely, blunt or slightly rounded. The common name of heart-leaf sida suggests roundedness of the lobes at the base. Cordifolia from the Latin means heart-shaped leaves.

Five veins spread across the leaf blade from its base, the central one a midrib, the outer pair small. More lateral veins emerge from the midrib higher up. The lateral veins curve in slightly and branch to the outside, more so near the margin. These veins are recessed above, prominent below, sometimes cream or yellower than the blade. The margins are irregularly serrated. 

The leaf surfaces are dull to dark green or yellow-green, paler below. Average leaf dimensions are 6 cm long by 4 cm wide (Pooley, 1998; Van Wyk and Malan, 1997; Onderstall, 1996; Leistner, (Ed.), 2000; iNaturalist).