Strelitzia caudata is unbranched and multi-stemmed, growing up to ± 6 m tall with a stem diameter of 100 to 150 mm. The older stems are woody with leaf scars and often have suckers at the base. Leaves are tufted at the apex; the petiole is pink, 1.5-1.7 m long and narrowed towards the base; the leaf blade is oblong, 1.5-1.7 m long and 800-850 mm broad. The leaves are leathery, opposite, green to greyish and the leaf blade becomes torn and tattered by wind as it ages.

The inflorescence consists of a single purplish, boat-shaped spathe bearing several flowers in autumn to winter (May to July). The spathe is at right angles to the peduncle, claret- coloured and glaucous, 300 mm long, 60-65 mm high and about 35 mm thick. It tapers to a slender tip and has mucilage exuding over the side which facilitates the emergence of flowers that are tightly packed. Sepals are white, sometimes mauve-tinged at the base, with the upper pair widely diverging from the lowest; the upper abaxial pair is linear-lanceolate 150-200 mm long and 30 mm broad. The lower sepal is about as long as the other two, boat-shaped, sharply keeled with the keel extending about its middle into a slender lobe or tail 15-25 mm long. Petals light mauve throughout or only towards the base, two lower ones about 120-150 mm long with basal portions forming a boat-shaped depression 20-30 mm wide, the apical portions form a sagittate (resembling an arrow-head) blade 80-100 mm long and 20 mm wide, with basal lobes obtuse, 50-60 mm long and 7-8 mm broad. The upper petal is ovate, 25-35 mm long including the cusp (sharp point) and 10-12.5 mm broad. The filaments are 30-40 mm long and anthers 55-90 mm long. The style is 160-175 mm long including the stigma. The ovary is irregularly triangular.

The fruit is a hard, woody, three-lobed capsule 50-70 mm long, 20-30 mm broad across the sides and splits from the apex in summer (November to February). The seeds are round, black to brown with a yellow aril.

It is difficult to distinguish S. caudata from S. alba and S. nicolai, the other tree-like strelitzias found in southern Africa, unless they are growing in their natural habitat (geographic locality), because they occur in different areas. Otherwise they can be separated by scrutinising their inflorescences. S. caudata is more closely related to S. alba and they both have simple inflorescences with a single spathe, but the petals of S. caudata are light mauve to blue with the basal lobes shaped like those of an arrow head and with a tailed lower sepal. The petals of S. alba are white with rounded lobes and the lower sepal is not prominently tailed. S. nicolai has blue petals and the inflorescence consists of several spathes.