Oldenburgia grandis is a shrub or small, gnarled tree. The emergent leaves are densely and completely felted with white hair. The flower-heads are borne on long, stout, velvety white stems (peduncles), which emerge from the centre of the rosette of leaves. Each flower-head resembles a giant thistle with its short, wide, purple brush covered thickly with velvety white hairs.