Plectranthus oertendahlii is a semi-succulent perennial reaching 20 cm in height. The trailing, square-shaped branches root at the nodes, helping the plant to anchor and spread in typical groundcover habit.

The opposite leaves are sessile, broadly ovate with obtusely angled tips. The leaf margins are serrated. Leaf surfaces are sparsely hairy as are the stems, silvery markings occur along the leaf veins. The lower leaf surfaces are purple with colourless gland dots. Leaves become 3 cm to 4 cm long, 2,5 cm to 4 cm wide.

The distribution of this rare species is small, occurring in the Oribi Gorge in southern KwaZulu-Natal and across the border in the Eastern Province. Its habitat is forest floors, shade areas of wooded river valleys (Pooley, 1998; www.plantzafrica.com).