Z. odorata may be separated from Z. aethiopica, the only other species occurring in the Cape, by the comparatively narrow, undulate spathe, the considerably shorter spadix borne on a distinct stipe and the larger green fruits which bend to the ground on ripening. It also has a much shorter flowering season.
Deciduous perennial herb up to 0.75 m tall. Rhizome tuberous, erect, ovoid to pyriform; up to 40 mm long and 25 mm wide; skin light fawn-coloured with thin chestnut-brown scales, cream-coloured internally; lateral buds give rise to daughter tubers. Roots numerous arising from the lower half of the rhizome, more basal ones becoming contractile towards the end of the growing season. Leaves erect, 2-3, up to 600 mm long; petiole up to 280 mm long and 10 mm wide, winged and partially sheathing for about 100 mm at the base, semi-terete above, light green, spongy; lamina broadly ovate- cordate up to 270 mm from petiole insertion to apex and 350 mm from lobes to apex, 80-160 mm wide, apex obtuse or acute, often ending in a curved apiculus about 15 mm long, green, immaculate, conspicuously veined. Peduncle erect, up to 550 mm long and 15 mm wide at the base, roughly triangular in cross section, light green, spongy, upper part becoming flaccid as fruit ripens and bending to the ground. Spathe up to 125 mm long and 80 mm wide, ovate, basally folded from below the insertion of the spadix with edges slightly overlapping for about 40 mm, spreading above, green abaxially shading to milk- white towards the apex, milk-white adaxially with a curved green apiculus about 20 mm long; margins somewhat undulate. Spadix shortly cylindrical up to 35 mm long on a stout stipe 8-10 mm long and 5-6 mm diameter. Male zone apical up to 25 mm long and about 12 mm wide towards the base tapering to 7 mm apically. Anthers yellow, about 1.5 mm in diameter with two pores producing strings of white pollen. Female zone basal, about 10 mm long and 13 mm wide. Ovaries broadly ovoid to globose about 3 mm long and wide, pale green, interspersed with staminodes. Style 0.75 mm long, white. Stigma rounded, white, becoming brown with age. Ovules up to 12 in 3 locules, pear-shaped, about 1 mm long, soft, white. Fruits up to 35 in a cluster about 75 mm long and 40 mm wide partially surrounded by the spathe remains; each fruit about 13 mm in diameter, firm, green, with a persistent style 1-2 mm long; becoming fawn and soft as they wither on the ground. Seed irregularly ovoid, 4-5 mm long and 3-4 mm wide, light chestnut-brown, 3-4 per fruit.
Koppies are formed of large doleritic boulders which break down to form a red clay soil which retains water well in the rainy season. The plants grow in the crevices between the boulders, where the lower part of the plant at least is in cool shade. The roots are in seasonally very wet soil or sometimes in standing water.