Prostanthera denticulata, commonly known as rough mintbush, is a shrub that is native to south-eastern Australia It has a low, spreading habit, growing to 1 metre high. The leaves are 4 to 10 mm long and 2 to 3 mm wide. The flowers are mauve or purple and appear in spring and early summer.The species was formally described in 1810 by Robert Brown. It occurs in New South Wales and Victoria.