The leaf shape of Protea cordata gave the heartleaf sugarbush its name. The heart-shaped leaves are sessile, i.e. without petioles (stalks). The leaves are glabrous (hairless) and glaucous (blue-green) to greyish in colour.
Young leaves can here be seen to have a pinkish tint, especially towards the margins. Pale yellow or reddish veins radiate from the base without visibly reaching the margins. Leaves become up to 16 cm wide and 14 cm long. The leaf-base may be elaborately lobed past the stem when mature. The rounded, entire margins peak in an inconspicuous tip. Leaves are spaced singly on the erect or sometimes drooping stems (Rebelo, 1995; Rourke, 1980; iNaturalist).