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Zieria laevigata

Smooth Zieria, Twiggy Midge Bush, Angled Zieria

Family: Rutaceae

An erect shrub to a height of 1.5 m.

It had a widespread natural distribution, growing mostly north of Jervis Bay (with a few records around Braidwood); extending north through Nowra and the southern highlands, through Sydney and the Blue Mountains to east of Kandos. There is then some disjunction in the distribution, with scattered mid and far north coast records, which extend to Brisbane; with another cluster of records in the northern tablelands, between Tamworth and Warwick in Queensland.

It is typically found in heathland and dry sclerophyll woodland and forest, on
skeletal sandy soils as well as granite.

The branches have prominent ridges which aid identification and are mostly hairless.

Zieria spp. have leaves arranged in opposite pairs, compound with three leaflets (tri-foliolate) or one leaflet (uni-foliolate). When trifoliolate, 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, the leaves are tri-foliolate, with leaflets elliptic to linear, to 40 mm long and to 3 mm wide, without warts and with margins crenate (wavy) and rolled under; upper surface deep green, lower surface paler to white.

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, the flowers are produced in leaf axils, in clusters of 3 usually; however, they can number up to 25, with clusters about the same length as the leaves; white to pale pink and occurring from August to December.

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 this species, the fruits are glabrous with scattered warts.


In the garden

Not widely found in cultivation. However, there is some suggestion from online resources that it is cultivated to a limited extent. It would be a useful and attractive plant in the garden, likely needing a well-drained sandy soil in full sun. Flowers attract bees. Likely a plant that needs more experimentation and exposure.

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.

Propagation

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

Other information

Zieria is a genus strongly odoriferous 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.

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.

laevigataLatin – meaning “smooth” or “slippery” – referring to the smooth texture of the leaves.

This species is not considered to be at risk of extinction in the wild.

NSW Flora Online (PlantNET) – Zieria laevigata profile page

https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Zieria~laevigata

Wikipedia – Zieria and Zieria laevigata profile pages

https://en.wikipedia.org/wiki/Zieria

https://en.wikipedia.org/wiki/Zieria_laevigata

Australian Plants Society – Sutherland Group – Coastal plants of Royal NP – Zieria laevigata profile page

https://sutherland.austplants.com.au/rnp/pl288.htm

By Jeff Howes, edited Dan Clarke