Prostanthera palustris, commonly known as swamp mint-bush,[2] is a species of flowering plant in the family Lamiaceae and is endemic to a restricted area of New South Wales.

It is a low, spreading, weak shrub with spatula-shaped leaves and pale mauve and white flowers with yellow spots in the petal tube.

Prostanthera palustris is a low, spreading, weak shrub that typically grows to a height of 0.2–0.3 m (7.9 in – 11.8 in), is not aromatic, and has branches with two longitudinal ridges.

[2][3] Prostanthera palustris was first formally described in 1997 by Barry Conn in the journal Telopea from material collected in Bundjalung National Park in 1990.

[3][4] Swamp mint-bush grows in wet coastal shrubland and heathland in the Jerusalem Creek area of Bundjalung National Park.