The narrow, grey leaves of Athanasia tomentosa are sessile (stalkless), alternate and somewhat overlapping, ascending up the stems.

The leaf shape is oblong to linear with visible midribs and rounded to pointed tips. The leaf is grey, covered in silvery grey hairs that are short and velvety. Leaf dimensions are 15 mm to 55 mm by 2 mm to 5 mm.

Tomentose in botany means covered in matted woolly hairs. The Latin word tomentum means stuffing for a cushion.

Old stem parts below usually lack leaves, the bark pale grey in colour (Vlok and Schutte-Vlok, 2010; Leistner, (Ed.), 2000; iSpot).