Bauhinia petersiana subsp. macrantha is an evergreen shrub or small tree, 1–3 m tall, and can reach a height of 8 m. It can also be successfully grown as a scrambler. The young branches display hairy bark and are often covered with tiny, orange scales; in contrast to this, the older branches tend to turn grey, smooth and the flaking of the older branches is quite common. The leaves are simple and deeply 2-lobed and produce hairs on the lower surface; about 9 conspicuous veins can also be observed on the underside of the leaves. The margins are entire and the leaf stalks up to 10 mm long.

The large flowers have 80 mm-long crisped petals, white with undulating margins; staminodes (sterile stamens) can be 4 or 5, and the hairy style can reach a length of up to 40 mm. Flowering is in midsummer, from December to January.

The fruit takes the form of a pod which is about 65–240 × 15–30 mm, is very hard and turns dark brown when matured.

The species B. petersiana is divided into 2 subspecies: subsp. macrantha and subsp. petersiana. They can be distinguished by their flowers, subsp. macrantha has broader, more rounded petals and shorter stamens, and it has a smaller growth habit with a tendency to scramble, whereas, subsp. petersiana is usually a large shrub or small tree over 2 m.