This is a short, thick-set tree, rarely exceeding 5 m in height. It is sparsely branched with grey, longitudinal fissured, thick and corky bark. The stem is thick and squat. This plant is considered a pachycaul succulent on the basis of its swollen stem base or tuber which forms early in plants grown from seed. Roots are also thick and swollen. The tree is slow growing.

The large, digitately compound, cabbage blue leaves are one of its most distinctive features. The leaf colour is in some part due to the thick waxy layers on the leaves, which may help protect them against severe frosts. The leaves are composed of 7-9, but sometimes up to 13 leaflets, springing from the end of a long stalk. The leaflets are up to 30 cm in length and the overall leaf can reach 60 cm. The leaflets of some forms are deeply lobed. New leaves are brighter green and emerge in a spring flush at the ends of branches.

There are two subspecies of Cussonia paniculata. The smaller mountain cabbage tree C. paniculata subsp. paniculata has leaflets without lobes and has a limited distribution in Eastern Cape. C. paniculata subsp. sinuata forms a larger tree with deeply lobed leaves and is more widespread. This is the form more commonly found in cultivation.

From January to April these trees bear small, green, stalked flowers; in short dense spikes, making up a large, branched inflorescence at the end of the trunk or branches. Flowers are followed by fleshy and purple-maroon fruits, which mature in May to June.