Nature conservation

Threatened species

Tranquility Mintbush - profile

Indicative distribution

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The areas shown in pink and/purple are the sub-regions where the species or community is known or predicted to occur. They may not occur thoughout the sub-region but may be restricted to certain areas. ( click here to see geographic restrictions). The information presented in this map is only indicative and may contain errors and omissions.
Scientific name: Prostanthera askania
Conservation status in NSW: Endangered
Commonwealth status: Endangered
Gazetted date: 12 Jun 1998
Profile last updated: 12 Aug 2019


An erect but spreading and sometimes scrambling, openly-branched shrub that grows from 1 – 3 metres high. The branches and leaves are strongly aromatic and densely covered with long, spreading hairs. Leaves are ovate (12 – 25 mm) long, dull dusty green in colour, with deep incisions forming lobe-like teeth, which are directed forwards. Flowers are pale mauve to mauve.


Occurs over a very restricted geographic range (of less than 12 km) in the upper reaches of creeks that flow into Tuggerah Lake or Brisbane Water within the Wyong and Gosford local government areas. Eight populations are known from the catchments of Ourimbah Creek, Narara Creek, Dog Trap Gully, Chittaway Creek and Berkeley Creek. A further two populations are known from the Erina Creek–Fires Creek catchment. The species may also have occurred in West Gosford.

Habitat and ecology

  • Occurs adjacent to, but not immediately in, drainage lines on flat to moderately steep slopes formed on Narrabeen sandstone and alluvial soils derived from it.
  • Occurs in moist sclerophyll forest and warm temperate rainforest communities, and the ecotone between them. These communities are generally tall forests with a mesic understorey; Sydney Blue Gum Eucalyptus saligna and Turpentine Syncarpia glomulifera are usually present, though canopy species present can be highly variable.
  • Ecological knowledge about this species is very limited.
  • The species is likely to be fire-sensitive given the moist forest habitats it occupies, however, its fire ecology is currently unknown.
  • May be a colonising species that takes advantage of increased light following natural canopy-cover disturbance. May be out competed by invading weed species such as Lantana.
  • Appears in some locations to propagate vegetatively by ‘stem-layering’ where prostrate branches take root where they remain in contact with the soil. This characteristic and the species’ tendency at many sites to form dense clumps make accurate counting of individual plants within populations difficult.
  • Flowering usually occurs in spring, however, it is known that the timing of both flowering and fruiting can be variable.

Regional distribution and habitat

Click on a region below to view detailed distribution, habitat and vegetation information.


Recovery strategies

Activities to assist this species

Information sources

IBRA Bioregion IBRA Subregion Known or predicted Geographic restrictions region
Sydney BasinPittwater Known North of the Hawkesbury River
Sydney BasinWyong Known South of Wyong River in Central Coast LGA