The stalked flower of Grewia robusta has the Grewia generic feature of both sepals and petals being flower-coloured on the inside, the petals in the inner whorl of five. The outside surfaces of the longer sepals are pale green to whitish, while the outsides of the shorter petals are similarly floral-coloured as the insides.

The ample cluster of stamens have the deepest colouring of the overall flower in their filaments, the evenly spread anthers in position for touching pollinating insects that will surely visit. The taller style holds the stigma prominently positioned for capitalising on such visitations as well.

Flower diameter is from 1,5 cm to 2,5 cm (Vlok and Schutte-Vlok, 2015; Shearing and Van Heerden, 2008; Coates Palgrave, 2002; iNaturalist).