The Natal Wild Banana grows up to 12m high and 4m wide. It is an evergreen tree with multi-stems that form dense clumps. The stem is woody and smooth in texture. It is light to dark grey and marked with old leaf scars. Attached to the stem by long, thick leaf stalks are the enormous, opposite leaves that are shiny and grey-green, with blades capable of reaching up to 2m in length. These tear in the wind and come to resemble giant feathers. Although not related to the true bananas or the wild banana Ensete ventricosum, the leaves and growth habit of S. nicolai are somewhat similar and probably account for the common name.
The flower of the Natal Wild Banana is a typical Crane Flower inflorescence, up to 500 mm long. The flowers of this tree have white sepals with blue petals and consist of 5 purplish blue, boat-shape sheaths.The whole flower resembles the head of the bird, with a white crest and purple beak. The tree flowers throughout the year with a peak in spring-summer. The inflorescence is compound (more than one flower).
The seeds are black in colour, with a tuft of a bright orange woolly aril on the lobe. They are produced mostly in autumn and winter, March to July.