The leaves of Pteronia incana are grey and woolly or felted. The common name of asbos (ash bush) is derived from the leaf colour. The leaf shape is oblong to obovate. Leaf tips vary from pointed to rounded or almost square. Leaf dimensions are about 5 mm by 3 mm; occasionally some atypically long ones do occur.

The leaves contain strongly aromatic oils that have been used commercially as essential oils. These oils probably cause the plant to be less important as fodder for stock.

In this picture the oblong buds are still hiding the disc florets under their yellow-green involucral bract covering. Bare stem parts appear quite dark here (Vlok and Schutte-Vlok, 2010; iSpot; www.renu-karoo.co.za).