"boronia rosmarinifolia" is an erect, woody shrub with many branches that grows to a height of about . it has simple, linear to oblong leaves that are long and wide with the edges turned down or rolled under. the flowers are pale to bright pink, rarely white and are usually arranged singly in leaf axils on a pedicel long. the four sepals are hairy, egg-shaped to triangular, long and wide but gradually increase in size as the fruit develops. the four petals are long and wide and enlarge as the fruit develops. the eight stamens alternate in length with those near the sepals longer than those near the petals. the style is glabrous. flowering occurs from july to october and the fruit is a usually glabrous capsule long and wide.