Prostanthera calycina

Family: Lamiaceae
Distribution: Eyre Peninsular, South Australia, in mallee vegetation on sandy-loam.
Common Name: West coast mintbush
Conservation Status: Listed as Vulnerable under the EPBC Act* (ie. facing a high risk of extinction in the wild in the medium-term future because it has a restricted distribution and fragmented habitat. Classified as 2VCi under the ROTAP* system.
Derivation of Name: Prostanthera…from Greek prostheke; an appendix and anthera; an anther, referring to the appendage on the stamens
calycina… From Greek calyx, a calyx and the suffix -inus, resembling or owning, referring to the conspicuous calyx of this species.

General Description:

Prostanthera is a genus of about 90 species which occur only in Australia. They are known generally as “mint bushes” because of the aromatic foliage of many species. As a member of the Lamiaceae, Prostanthera is related to a number of culinary herbs such as mint, thyme, oregano and sage.

Prostanthera calycina is a spreading shrub to about 50 cm in height. The leaves are oval to oblong, about 10 mm in diameter and covered in microscopic hairs and highly aromatic. The tubular flowers occur in spring and early summer and are usually dull red in colour subtended by a large green or maroon calyx.

P.calycina is best suited to dry climates and can be short lived in areas with humid summers. It prefers a well drained position and will tolerate full sun as well as partial shade. Prostantheras respond to well to annual fertilising after flowering and are not as sensitive as some other Australian plants to phosphorus.

Propagation is easy from cuttings but seed can be slow to germinate. It can also be grafted using one of hardier mint bushes such as P.nivea as rootstock. Unlike most other prostantheras which can be grafted onto the related (and extremely hardy) Westringia fruticosa, P.calycina is not compatible with that species.