The cluster of Asclepias eminens buds busy forming the flat-topped inflorescence in picture resemble vertically ridged or angular green urns, ending in white-rimmed openings that are five-angled to rounded.

The simple, nearly sessile leaves ascend in spaced, opposite pairs from the stems. They are narrowly linear, tapering to acutely pointed tips, their bases eared. The leaves are from 10 mm to 105 mm long and from 1 mm to 6 mm wide.

The conspicuous cream-coloured leaf midribs are comparatively wide and visible on both surfaces, sometimes scaled below. The blade halves fold in laterally, their thickened margins rolled under. The leaves may be hairy, sometimes glabrous (meaning not hairy) (Pooley, 1998; Van Wyk and Malan, 1997; JSTOR; iNaturalist).