The flowers of Pelargonium ribifolium grow few to several-flowered in axillary and stem-tip umbels on longish peduncles. The calyx tubes have characteristic angled knobs where they join the pedicels. The five calyx lobes of each flower are oblong, ending in acutely pointed and sometimes recurving tips.
The white flower is two-lipped, the upper petal pair bigger than the narrow, lower three and sometimes marked in purplish red lines near the base. Flower diameter is about 20 mm, the calyx tube up to 8 mm long. The anthers are orange, no longer present in the flowers of the photo.
Flowering happens most in spring and summer, but sometimes throughout the year (Vlok and Schutte-Vlok, 2015; Bond and Goldblatt, 1984; iNaturalist).