The white-stem thorn is a large, erect tree that grows to an average height of 10-15 m, exceptionally large trees may reach a height of 25 m. The stem of younger trees appears yellowish with papery bark and persisting prickles. As it gets older, the bark gets smoother and whitish grey, with bark flakes sometimes present. Young branches are covered in silvery hairs and the whole tree is covered in dark brown to black hooked thorns in pairs.

The leaves are twice compound with 14-35 pairs of pinnae and 20-60 leaflets per pinna. Leaves are fairly large and arranged singly along the shoots. The upper surface of the leaves is darker than the underside, and mostly with hairs on the margins and on the leaf stalk. The flowers that appear from September to December are light yellow to cream. The flowers as well as the seedpods are borne in spikes, which arise from the nodes. They can appear singly or in clusters of up to four and are sweetly scented.

The seed pods are flat and appear shiny green, turning to a light brown colour as they ripen and then dry out. The number of seeds per pod varies from 3 to 10 and they are also fairly flattened, and dark brown when ripe.