Greyia radlkoferi is a large shrub or small tree, growing 2-4 up to 5 m in height. The branches have yellowish smooth bark when young, turning grey and deeply furrowed as the tree ages. The leaves are oval to heart-shaped, coarsely toothed and lobed at the base, sparsely hairy above and deeply woolly underneath, a characteristic that gives this tree its common name and distinguishes it from its more commonly planted cousin G. sutherlandii, the glossy bottlebrush. The petioles of G. radlkoferi are also very hairy and the longest of all three species.

The dense clusters of flowers are deep scarlet, blooming in upright racemes. The individual flowers are 20 mm long, with deep red stamens projecting from the mouth of the petal tube, which are slightly narrowed at the base. The 80 mm long racemes are borne at the end of the stems, before or with the new leaves, in winter to spring (July to October), which makes them all the more conspicuous. The cylindrical fruit capsules split open at one end to release seeds in the autumn.