Prostanthera nivea var. induta is a dense medium shrub that reaches a height of about 2 metres by 1 metre wide.
This variety taxon is only known from north-western NSW, growing in the Warrumbungle Ranges and Pilliga areas.
It is typically found in heath on rocky slopes in crevices or on ledges in shallow soils.
Prostanthera have simple, opposite and usually odorous leaves. In this species, the leaves are linear, to 1 cm long and only 2 mm wide, grey-green and held in small clusters. Unlike most Prostantheras, var. induta has little or no foliage aroma.
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 in leaf axils, mostly solitarily but arranged in long leafy spikes; white to mauve with yellow spots in the throat.
Fruits are mericarps (can be called nutlets). Four are produced produced at the base of the calyx.
Back in the 1970s we lived and worked in the Warrumbungle National Park. Our house was situated at the western end of the park at the foot of Chalker’s Mountain. One day during our first spring we went for walk along a wooded ridge, north of the house. At the top of the ridge we found ourselves shoulder deep in masses of a mintbush in full flower. This is one of our enduring memories of our time in the Warrumbungles. The fact that we nearly tripped over a sleeping feral pig, at the same time, is another story.
Subsequent investigation identified the mintbush as Prostanthera nivea var. induta.
After leaving the Warrumbungles, we lost touch with this splendid plant but after moving to Armidale found that an Australian Plants Society member had a specimen in his garden. A kind donation of cuttings means that there are places where we are again shoulder deep in Prostanthera nivea var. induta this time in our garden west of Armidale.
Even back in 1978 the late George Althofer maintained in his beautiful book The Cradle of Incense that var. induta was worthy of species status.
A wonderful addition to any garden, in a shady spot. It is reasonably hardy and a great feature shrub. It is commonly sold at native nurseries.
In our garden, during dry spells, many Prostantheras tend to wilt. This variety has proved to be wilt-resistant. The eye-catching, conspicuous and profuse flowers are mauve and one centimetre across. Blooms begin to appear in spring and are carried into summer. Of all the mintbushes that we grow, this variety has the longest flowering period.
Pruning is advised as this will keep plants from becoming straggly and promote more flowers.
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.
Another virtue of this variety is that propagation from cuttings is rapid.
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.
The type specimen was collected by Charles Moore, an early director of the Royal Botanic Gardens, Sydney, along the Castlereagh River prior to 1870.
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.
nivea – Latin meaning “snow” or “snow-white” – referring to the dense and appressed white hairs on this species.
var. induta – Latin – meaning “clothed” – referring to this variety having very dense hairs.
This variety taxon is not considered to be at risk of extinction in the wild. However, it only grows in the Warraumbungle and Pilliga areas, and is considered rare.
NSW Flora Online (PlantNET) – Prostanthera nivea var. induta profile page https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=in&name=Prostanthera~nivea~var.+induta
Wrigley, J.W. & Fagg, M.I. (2001). Australian Native Plants – Propagation, cultivation and use in landscaping. 4th edition. New Holland Publishers, Pty. Ltd. Australia.
All Natives Nursery – Prostanthera nivea var. induta sales page https://www.allnatives.com.au/shrubs/1-to-3m-high/snowy-mint-bush-prostanthera-nivea-var-induta