It is a soft-wooded, semi-evergreen upright shrub or small tree, usually 2.5–4.5 metres (8–15 ft) tall. Similar in appearance to the unrelated “jade plant” Crassula ovata (family Crassulaceae), P. afra has smaller and rounder pads and more compact growth (shorter internodal spaces, down to 1.5 millimetres (0.059 in)). It is much hardier, faster-growing, more loosely branched, and has more limber tapering branches than Crassula once established.
The genus Portulacaria has been shown to be an outlier, relatively unrelated to the other genera in the family, which are all restricted to small ranges in the arid far west of Southern Africa.