An erect and strong shrub to 2 metres tall.
It has a very large, mainly coastal distribution, growing from eastern-central Victoria, along the entirety of the NSW coast and eastern tablelands, mostly within 150 km of the ocean, into Queensland, as far north as Cairns. It extends as far inland as Tamworth and Armidale in NSW, and near Rolleston in Queensland.
It can be found in dry and wet sclerophyll woodland and forest as well as coastal shrublands.
The branches have ridges when young, with warty protuberances with varying degrees of stellate hairs.
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, the leaves are tri-foliolate, with leaflets narrow-elliptic to lanceolate (wider end at the apex), to 45 mm long and to 7 mm wide, upper surface dark green, dotted with oil glands, and lower surface paler with scattered hairs or hairless, strongly aromatic.
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 arranged in clusters of 7 to 60 flowers, in leaf axils with the clusters usually shorter than the leaves; white, about 8 mm in diameter; occurring in spring and summer.
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 cocci have warty protuberances, are hairless, and have a small oil body attached (elaisome).
This is one of the more commonly grown Zieria species and with good success.
This author has been growing this plant for many years in a northern Sydney garden. Plant in a dappled-light to shady position. Give a good prune after flowering.
Best to ensure that the soil has some drainage, especially in wet times.
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.
Some species are more commonly grown. They require good drainage, preferably on a light sandy soil and a semi-shaded area. They have soft foliage, can be pruned into nice-rounded shrubs and can flower prolifically.
In common with most members of the Rutaceae, propagation from seed is difficult but cuttings usually strike readily from current season’s growth.
It appears the common name arose from its use as an insect repellent. When the leaves are crushed, they secrete bitter aromatic oil high in safrole, which is not particularly pleasant to me. These oil glands are quite noticeable in the close up photos attached.
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. NSW currently has about 34 species; several listed as threatened.
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.
Zieria – named 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.
smithii – named in honour of James Edward Smith (1759 – 1828), English botanist and founder of the Linnaean Society.
NSW Flora Online (PlantNET) – Zieria smithii profile page https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Zieria~smithii
Growing Illawarra Natives – Zieria smithii profile page https://finder.growingillawarranatives.org/plants/plant/527
Wrigley, J.W. & Fagg, M.I. (2001). Australian Native Plants – Propagation, cultivation and use in landscaping. 4th edition. New Holland Publishers, Pty. Ltd. Australia.