It has smooth bark, linear to narrow lance-shaped or narrow elliptical adult leaves, flower buds in groups of up to thirteen, pale lemon-coloured flowers and barrel-shaped, cylindrical or conical fruit.

Eucalyptus phaenophylla is a mallee that typically grows to a height of 1 to 6 metres (3 to 20 ft) and forms a lignotuber.

It has smooth grey to brownish bark that is shed in ribbons and sometimes accumulates near the base.

[7] In the same paper, Brooker and Hopper described two subspecies and the names have been accepted by the Australian Plant Census: Common southern mallee is found on gently undulating sand plains, breakaways and ridges between Wickepin and the Ravensthorpe Range, where it grows in species-rich mallee communities.

[3] In 2019 the International Union for the Conservation of Nature listed E. phaenophylla as a vulnerable species noting that although it has a stable population, it is severely fragmented with a continuing decline of mature individuals.