Ptilotus capensis is an erect perennial herb or shrub that typically grows up to about high with linear leaves. The flowers are dull green, red-streaked when fresh, and densely arranged in spikes mostly long and wide. The bracts are narrowly lance-shaped, long and the bracteoles are long. The tepals are linear up to long, there are one or two fertile stamens and several staminodes, and the style is about long.