Kunzea petrophila is a spreading shrub which usually grows to a height of with its young branches and leaves covered with often woolly hairs. The leaves are arranged alternately, linear to narrow lance-shaped, long about wide without a
petiole. The flowers are arranged in groups of between ten and eighteen near the ends of the main branches, or in smaller groups on short side shoots. The flowers are
sessile with
bracts and
bracteoles at the base of the flowers. The
floral cup is hairy, about long when flowering with the
sepal lobes long and pointed. The
petals are cream-coloured, broadly egg-shaped to almost round and long. There are 40–46
stamens which are long. Flowering has been observed in May, August and November. ==Taxonomy and naming==