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Zieria aspalathoides

Whorled Zieria / Heath Zieria

Family: Rutaceae

A shrub resembling a heath-plant, growing to a height of 1.5 metres by 1.5 metres wide.

It is found in inland areas of NSW, over most of the western slopes, extending into the tablelands and south-western plains. It grows as far north as north-west of Cairns in Queensland (where it grows closer to the coast), extending south to around Griffith and Wagga Wagga in NSW, with a disjunction to a few records in Central Victoria.

It grows in dry sclerophyll forest and heath, often on sandy soils and amongst rocks.

The branches have ridges and are scaly or hairy, at least when young.

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 three linear to lanceolate leaflets, to 8 mm long and to 1.5 mm wide. With such dimensions, the foliage appears to be in whorls of six leaves. The upper surface of each leaflet is darker green compared to the lower surface.

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 pale to deep pink, arranged in clusters of mostly three, with clusters extending beyond the leaves, occurring from late winter to early 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 fruit contain one or two seeds, are hairless and have an appendage (elaisome).

In the garden

This species is known to be cultivated but is reported to be difficult. Not a great deal is known. It may be more readily cultivated in the future. It grows naturally on sandy soils in drier areas. Check local native nurseries for stock. It is reported to be a good rockery plant in full sun. However, excellent drainage is essential.

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.

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

Two subspecies are described for this species, one of which is recognised in NSW:

  • subsp. aspalathoides – longer leaflets (more than 4 mm long) and occurring over the range in NSW;
  • subsp. brachyphylla which has leaflets less than 3 mm long, occurring in Qld.

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.

aspalathoides – Latin – refers to a perceived similarity to plants in the genus Aspalathus – a genus of pea-species, mostly found in South Africa.

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

NSW Flora Online (PlantNET) – Zieria aspalathoides profile page
https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Zieria~aspalathoides

Wikipedia – Zieria and Zieria aspalathoides profile page
https://en.wikipedia.org/wiki/Zieria
https://en.wikipedia.org/wiki/Zieria_aspalathoides

Wrigley, J.W. & Fagg, M.I. (2001). Australian Native Plants – Propagation, cultivation and use in landscaping. 4th edition. New Holland Publishers, Pty. Ltd. Australia.

By Jeff Howes. Editing and additional text by Dan Clarke