Botanic Gardens Trust, Sydney, Australia


Be inspired to grow your own ‘Mint Velvet’

Mark Viler, Senior Horticulturist, Commercial Production
The Australian Botanic Garden, Mount Annan

You may not be aware that the Trust has a small commercial production unit based at the Australian Botanic Garden, Mount Annan. The aim is to help promote the amazingly beautiful flora of New South Wales through the release of wild sourced native plants to the nursery industry and in turn raise awareness of the conservation activities of the Trust. We have a number of licensed growers who grow our plants and distribute labels to retail markets in Queensland, the ACT, South Australia, Victoria, Western Australia and New South Wales.

The first of those plant releases coincided with the centenary of federation celebrations and saw the introduction of the Federation Star™ flannel flowers with ‘Starbright’ being the flagship plant. Starbright continues to be very popular in the retail sector and is now grown and sold across Australia.

The latest addition we are delighted to introduce is the rare and endangered NSW species Prostanthera densa ‘Mint Velvet’. With permission from National Parks and Wildlife, this is the first threatened species from our collection to be made available to the general public. As a result of restrictions on commercialisation of endangered species they are scarcely found in the nursery trade. While the number of rare and endangered species in NSW at the time of writing stands at 611, this is likely to increase as climate impacts on marginal plant communities. Not all are suitable for horticultural applications or the confines of a commercial production system; we aim to learn from our experiences at Mount Annan to select and trial those with most potential. The creation of PlantBank, our new research facility, is also contributing to their preservation and conservation through seedbanking and propagation research. Through the sale of these plants we hope to further inspire the appreciation of those efforts.

While releasing rare species such as ‘Mint Velvet’ may help their preservation, we also use plant labelling to raise awareness of threats posed to plant habitat, the protection of which will ultimately decide the plant’s future. 

Prostanthera densa ‘Mint Velvet’ is also known as the villous mint bush, and like all mint bushes comes from the family Lamiaceae. This aromatic compact and erect shrub grows from 0.5 -2 m tall but is more commonly found growing at around one metre. The densely hirsute mid-green leaves occur in pairs, are almost triangular in shape with strongly recurved margins. The flowers are pale mauve to mauve with white and orange markings in the throat, and can occur sparingly throughout the year but are chiefly seen in spring from October to December.

The species can be found growing in sclerophyll forest and shrubland on coastal headlands and near coastal ranges on well drained sandstone soils and rocky slopes. 

Prostanthera densa is seen from Nelson Bay to Beecroft Peninsula, NSW. It has been recorded in the Currarong area of Jervis Bay, along with other known localities in Bass and Flinders Point in Cronulla, Garie Beach in the Royal National Park, and Gan Gan Hill, Nelson Bay which is where this variety, ‘Mint Velvet’, originates.

This plant is listed as vulnerable under Schedule 1 of the Endangered Species Protection Act 1992 (Commonwealth) and is also listed as vulnerable under Schedule 3 of the Threatened Species Conservation Act 1995 (NSW).

The main identified threat to Prostanthera densa is urban development, with potential threats including dieback caused by Phytophthora cinnamomi, and grazing by Rusa Deer (Cervus timorensis). It may also be threatened by inappropriate fire regimes, even though plants have been known to regenerate from rootstock after fire.

We hope you are inspired to grow your own ‘Mint Velvet’, pass on its story and feel a sense of pride that you are helping to conserve one of New South Wales amazingly beautiful plants in the process.