The Convolvulus capensis flower grows solitary from a leaf axil on a stalk of about 1,5 cm long. The silky calyx of up to 1 cm long has blunt-tipped lobes.

The corolla is mostly white, sometimes pale pink, pleated where the lobes are joined. The funnel-shaped corolla spreads widely. It is from 1,5 cm to 3,5 cm long and 3,5 cm in diameter.

The pale anthers protrude from the narrow throat. The style divides into two stigmas.

Flowering happens in spring, each flower lasting only one day. The fruit is a capsule as long as the calyx (Vlok and Schutte-Vlok, 2015; Manning, 2007; iNaturalist).