Zieria baeuerlenii

Bomaderry Zieria

Family: Rutaceae

An open shrub, with stems often trailing on the ground (procumbent), usually growing to a height up to 1 metre.

It is only found in occurring in only one location, north-west of Nowra in New South Wales, where it is has a habitat over about 50 hectares.

It is a listed threatened species.

It grows on skeletal sandy loam overlaying sandstone, on plateaus and amongst sandstone boulders in dry sclerophyll shrubby woodland and forest, as well as closed shrubby woodland.

The young branches have a velvet-texture due to stellate and longer hairs. The older branches become hairless.

Zieria spp. have leaves arranged in opposite pairs, compound with three leaflets (tri-foliolate) or one leaflet (uni-foliolate). When tri-foliolate, the leaflets are often similar in shape with the middle leaflet often larger, and with leaves usually strongly odorous, green to grey-green.
In this species, leaves are tri-foliolate with leaflets heart-shaped or obcordate (with the narrower end towards the base) to ovate / obovate, to 12 mm long and to 9 mm wide, with a velvet-texture and strong venation.

Zieria spp. have flowers arranged in groups (cymose clusters) in the leaf axils and have four sepals joined at the base and four petals, alternating with the sepals. There are four stamens and four fused carpels. In this species, flowers are pinkish-white, about 8 mm in diameter, arranged in clusters up to 7 usually (or more) in leaf axils, occurring between September and October

Zieria have a fruit described as a schizocarp-capsule which splits into segments called cocci (singular coccus). Fruit generally have four cocci, each containing one or two seeds.

In the garden

This species is listed as threatened with extinction and is only known from one area. Hence, it does not have a history of cultivation.

Wollongong Botanic Gardens reports:
In 2017, more than 300 endangered Zieria baeuerlenii that were grown at the Wollongong Botanic Garden were planted back into the wild. Sadly, the following year a large bushfire went through the replanted and wild population, burning most of the planted area. This was a big setback and loss for this endangered species. Amazingly, some of these plants (both wild and replanted) are showing their ability to survive and are re-shooting from their root plates underground.

Therefore, it may be available for cultivation (check local native nurseries) and may be more readily cultivated in the future. It grows naturally on shallow sandy soils on sandstone.

Many Zieria make interesting garden plants and deserve a place in gardens. They are a member of the Rutaceae family which include the genera Boronia, Philotheca and Crowea, all of which can be challenging to grow.


In this species, fruit / seeds are not produced.

Seed production has never been observed in the Bomaderry Zieria and all evidence collected to date suggests that the species has lost its capacity to reproduce sexually.

In common with most members of the Rutaceae, propagation from cuttings usually strike readily from current season’s growth.

Other information

Zieria is a genus of strongly odorous soft-woody shrubs, or small trees, with over 40 species described, all of which are endemic to Australia except for one species which is found in New Caledonia. They occur in all Australian states except Western Australia but the genus is under review and a number of species are yet to be described or the description published. NSW currently has 34 species, some which are species-complex.

Zieria are similar to the better known genus Boronia but can be distinguished by the number of stamens in the flowers – four and eight in Boronia.

Most Zieria would die in a bushfire and regenerate from seeds. Suckering from roots may be possible.

Zierianamed in honour of Jan Zier (d. 1793), by Sir James E. Smith. Zier was a Polish botanist and cryptogam (ferns, mosses, lichen and fungi) specialist, for which there is little information online. He assisted Jacob Friedrich Ehrhart, the Director of the Botanical Garden of Hannover.

baeuerlenii named after the German plant collector Wilhelm Baeuerlen (1840 – 1917) who moved to Australia in about 1883, and lived in the Shoalhaven area. He collected many specimens across eastern Australia for Ferdinand von Mueller and Joseph Maiden, and also collected in Papua New Guinea as well.

This species is threatened with extinction in the wild and is listed at both the State and Commonwealth level with the category of Endangered.

NSW Office of Environment and Heritage – Threatened Species Profiles –                                        Zieria baeuerlenii profile page    https://www.environment.nsw.gov.au/threatenedSpeciesApp/profile.aspx?id=10850

Friends of Bomaderry Creek – A Native Recovery Plan for the Bomaderry Zieria http://www.friendsofbomaderrycreek.com.au/saving-the-zieria.html

Wollongong Botanic Gardens – Rare and Threatened Plants – Zieria baeuerlenii https://wollongongbotanicgarden.com.au/collections-and-conservation/conservation/rare-and-threatened-plants/accordions/zieria-baeuerlenii-bomaderry-zieria

Wikipedia Zieria and Zieria baeuerlenii profile pages                          https://en.wikipedia.org/wiki/Zieria                                https://en.wikipedia.org/wiki/Zieria_baeuerlenii

By Jeff Howes. Editing and additional text by Dan Clarke.