Petrophile imbricata is a shrub that typically grows to a height of and has hairy young branchlets. The leaves are needle-shaped, up to about long and overlap each other. The flowers are arranged on the ends of branchlets in sessile, oval heads up to about in diameter, with many overlapping narrow egg-shaped involucral bracts at the base. The flowers are up to about long, cream-coloured and hairy. Flowering occurs from August to September and the fruit is a nut, fused with others in an oval to slightly cup-shaped head up to about in diameter.