Prostanthera caerulea, commonly known as lilac mint bush, is a species of flowering plant that is endemic to eastern Australia. It is an erect shrub with narrow egg-shaped leaves that have toothed edges, and white to bluish mauve flowers arranged on the ends of branchlets. Description Prostanthera caerulea is an erect shrub that typically grows to a height of with four-sided branchlets densely covered with glands. Its leaves are narrow egg-shaped, long and wide on a petiole long, and with slightly to strongly toothed edges. The flowers are arranged in groups on the ends of branchlets with bracteoles long at the base, but that fall off as the flower develops. The sepals are long forming a tube long with two lobes, the upper lobe long. The petals are long, forming a white to bluish-mauve tube. Flowering occurs from September to November. Taxonomy and naming Prostanthera caerulea was first formally described in 1810 by Robert Brown in Prodromus Florae Novae Hollandiae et Insulae Van Diemen. Distribution and habitat Lilac mint bush grows in heath and forest on sandy soil from south-east Queensland to Wollongong in New South Wales. References caerulea Flora of New South Wales Flora of Queensland Lamiales of Australia Plants described in 1810 Taxa named by Robert Brown (botanist, born 1773)