Prostanthera cryptandroides is typically a small shrub but can reach 2 metres in height by up to 1 metre wide. Young growth is sticky.
It occurs on the central and northen tablelands of NSW, in disjunct patches, growing around Glen Davis, then disjunctly around Denman in the Hunter Valley, then heavily around Warialda further north and over the border into Queensland between Texas and Boggabilla. It is very common in Queensland, growing north through the state, to as far west as Tambo and Pentland, and as far north as near-Townsville.
It grows mainly in dry sclerophyll woodland and forest, usually on rocky substrates.
Prostanthera have simple, opposite and usually odorous leaves. In this species, leaves are elliptic to ovate, to about 10 mm long and 3 mm wide, light to mid green and with the margins having conspicuous lobes (3 to 4) on each side; sticky to touch.
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 1.5 centimetres long, white to lilac with a purple-spotted throat; produced solitarily in leaf axils, profuse between September and April.
Fruits are mericarps (can be called nutlets). Four are produced produced at the base of the calyx.
P. cryptandroides is an attractive small shrub to use in native cottage gardens and rockeries.
Tip pruning is necessary to maintain foliage density and abundant blooming.
It is not a commonly cultivated prostanthera but some information is available that is can be cultivated. Check with local native nurseries for availability. It grows naturally on rocky soils so this sort of substrate may be beneficial in a garden setting.
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.
Propagation from cuttings usually presents no problems.
There are two subspecies are currenbtly recognised in NSW:
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.
cryptandroides – Latin – resembling the genus Cryptandra – a group of Australian plants in the Rhamnaceae family
(subsp. euphrasioides) – Latin – resembling the genus Euphrasia – a group of plants called ‘Eyebrights’ which are semi-parasitic; a genus with some Australian natives as well as cosmopolitan species).
The subsp. cryptandroides taxon is listed as threatened with extinction in the wild, at both the State and Commonwealth level with the category of vulnerable.
NSW Flora Online (PlantNET) – Prostanthera cryptandroides profile page https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Prostanthera~cryptandroides
NSW Office of Environment and Heritage – Threatened Species Profiles – Prostanthera cryptandroides subsp. cryptandroides profile page https://www.environment.nsw.gov.au/threatenedspeciesapp/profile.aspx?id=10673
Wikipedia – Prostanthera cryptandroides profile page https://en.wikipedia.org/wiki/Prostanthera_cryptandroides