The flowers of Passerina obtusifolia vary in colour from pale pink to dull red. This colouring is presented on four elliptic sepals spreading to a diameter of 5 mm; there are no petals. The sepals are joined in a flask-shaped tube of about 5 mm in length. Two unequal whorls of four stamens each present pale creamy yellow anthers, spreading conspicuously above the sepals.
Flowering occurs in spring and early summer. This specimen was seen in the Tradouw Pass in October (Vlok and Schutte-Vlok, 2010; Bond and Goldblatt, 1984; iSpot).