Prostanthera phylicifolia

Spiked Mint Bush or Mint Bush

Family: Lamiaceae

A rounded shrub that grows to about 1.5 to 2 metres high, with a similar spread.

It occurs mainly on the southern tablelands and south coast of NSW, from south of Canberram to Eden and Jindabyne-areas. It extends into north-eastern Victoria to as far south-west as Traralgon-area. There are some records around Orange-Dubbo and a cluster of records around the NSW-Queensland border; from south of Coffs Harbour to Warwick and the Gold Coast (it is not known if these are considered a different species).

It grows in shallow sandy soils, in heathland and dry sclerophyll woodlands and forests; usually on granite ridges and hillsides.

Prostanthera have simple, opposite and usually odorous leaves. In this species, leaves are to about 15 mm long and 4 mm wide, mid to dark green with strongly recurved margins.

Flowers have a shape described as labiate (applied to all Lamiaceae flowers) with petals varying in their size, purple to lilac, produced in leaf axils. One of the identification features for Prostanthera is that the 5 calyx parts (sepals; basal whorl of the flower) are fused into 2 lips. In this species, flowers are produced solitarily in leaf axils but in dense leafy clusters, close to the terminals, profusely in spring, white to pale purple with dark purple spots in the corolla throat and yellow spots on the lower lobe.

Fruits are mericarps (can be called nutlets). Four are produced produced at the base of the calyx.

In the garden

Author’s notes:

I have been growing Prostanthera phylicifolia for many years, in my garden in the northern Sydney suburb of Westleigh.

My plants are growing in a thin layer of topsoil over a clay sub soil in a well drained position and receive some additional watering in dry spells. They are very hardy and grow best in a position that does not receive full sun and prefer dappled light or shade. The only maintenance required is to give them a good pruning after each flowering to keep them compact and promote better flowering next season. I remove a third of the new growth.

This is a plant that will grow in shade. I made the mistake once of planting one in a position that receives morning dappled shade and full afternoon sun. This caused new sappy growth to wilt. When the sun leaves the plant, it recovers and still flowers spectacularly.

Some Prostantheas have a short flowering time. However, I find that this species flowers for me for well over a month in early Spring. They are reportedly frost resistant and are a favourite plant on the west coast of USA as well as England.

Prostanthera phylicifolia is stunning in flower as the pale violet/purple flowers contrast beautifully with the small dark green aromatic leaves.

A great addition to any gardens particularly in shade.

A Prostanthera in full bloom is a magnificent sight and there are so many colours to choose from for your garden. These plants are found in all states in varied soil conditions and climate and thus while it may be a challenge to grow some species many are easy in a garden situation.

A few basic growing tips are:
• Good drainage is essential. Raised beds ensure this
• Water new plants until established, weekly or as required.
• Do not over water, as this can induce root rot and fungal infestation.
• They prefer moist root runs.
• Plant drooping is an indicator of dryness

Positioning of prostantheras as border plants or near pathways is recommended as the mint odour is released when brushed against.


They strike very easily from cuttings (nearly between wet fingers).

Plants may be grown from fresh seed. However, cuttings are frequently and reliably used, usually semi-hard wood or soft tip material, which strike well in spring or autumn.

Other information

Prostanthera is a diverse group of about 100 species, endemic to Australia, occurring in all states. There are still many unresolved taxa and species complexes, with new forms regularly being found. Natural hybrids occur between several species and most species appear to be capable of hybridizing when in cultivation. NSW currently has about 52 species, some of which are species-complex and others which are threatened with extinction.

Some 80% of mints contain aromatic oils within their leaves with oil of cineole being a major component. Prostanthera sieberi, P. incisa and P. staurophylla are quite pleasantly overpowering in their exudates when crushed. Oil from the leaves of some species is distilled for use in cosmetics and as soap additives.

Likely regenerates from seed after fire, possibly after 12 months.

Prostanthera – from the Greek prosthike (προσθήκη) which translates to “addendum” (root of prosthetic), and anthir (ανθήρ) meaning anther – referring to the anthers which have an appendage of tissue.

phylicifolia – Latin – referring to foliage of the genus Phylica (in the Rhamnaceae family) in which most species come from South Africa.

This species is not considered to be at risk of extinction in the wild.

NSW Flora Online (PlantNET) – Prostanthera phylicifolia profile page https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Prostanthera~phylicifolia

Wrigley, J.W. & Fagg, M.I. (2001). Australian Native Plants – Propagation, cultivation and use in landscaping. 4th edition. New Holland Publishers, Pty. Ltd. Australia.

Gardeners World – Prostanthera phylicifolia profile page https://www.gardenersworld.com/plants/prostanthera-phylicifolia/

By Jeff Howes. Editing and additional text by Dan Clarke