The flowers of Psoralea sordida grow solitary or in clusters of up to three on short stalks emerging from lobed cupules in leaf axils. These cup-like structures at the base of flower stalks are features of the genus.
Flowers become 1,2 cm in diameter. They are pale blue with dark blue or purple colouring up the central fold of the comparatively large banner, the upper petal of the flower. Fine dark blue lines veer from this dark section to the sides of the banner. The wings are smaller, pale blue, almost white and rounded in shape. The keel is small and narrow, darker blue in colour.
Pollination is performed by carpenter bees that nest in the harder wooded Protea shrubs of the shared habitat. Psoralea generally grows fast, not forming much hard wood (Vlok and Schutte-Vlok, 2010).