Prostanthera petraea is a rare mint bush from the Northern Tablelands and perhaps southern Queensland.
Prostanthera petraea is a small to tall shrub. Plants in our garden are about two metres tall after three years in the ground. The leaves are ovate up to 8 centimetres long, 2 centimetres wide, strongly aromatic with prominent stalks. They are dull olive-green above and paler beneath.
Lobed flowers are two centimetres long, white, carried in terminal sprays and, in our garden, appear in early summer. Blooms are conspicuous and profuse. They are similar in colour and size to the flowers of the better known Prostanthera lasianthos.
Both foliage and flowers are attractive features. Light pruning is appreciated.
Prostanthera petraea deserves to be widely cultivated. Not only because it is a handsome, free-flowering shrub but because of its rarity. Extensive cultivation reduces the risk of extinction.
This native mint bush would be an interesting and aromatic addition to a native shrubbery.
Prostanthera petraea propagates readily from cuttings.
The species name refers to the large boulders amongst which the species grows. It also acknowledges the aboriginal place name Boonoo Boonoo, meaning large rocks.
The species was named in 2006. Some botanical publications, prior to 2006, list this mint bush as Prostanthera species B. Prostanthera petraea is found in Boonoo Boonoo National Park and other areas around Tenterfield on the Northern Tablelands of New South Wales. In Boonoo Boonoo National Park the species grows in close proximity to Prostanthera nivea ssp nivea. Very rarely do you find two mint bush species growing in close proximity in the wild.