Tetratheca shiressii

Pink-eyes, Black-eyed Susan

Family: Elaeocarpaceae

Small shrub to about 0.7 metres tall, often multi-stemmed with a radial spread to about 0.3 metres.

It is endemic to NSW, growing mainly in two disjunct patches on the central coast subdivision; between Wollongong and Sydney; and then from around Berowra – north through the Gosford area, to Watagan State Forest with some outlying records further west on Putty Road at Howes Valley. Interestingly, it is absent between Berowra and Botany Bay. 

It is generally found in heathland on rocky or sandy sites, as well as swamp-heath or wet heath. 

In Tetratheca spp., leaves are simple and can be arranged alternately or in opposite pairs or whorls. Some species can exhibit varying leaf arrangements (dimorphic). In this species, leaves are in opposite pairs or in whorls of 3 or 4 to 5, to 20 mm long and 1 mm wide, linear, with revolute margins. A second description is given for leaves on hairy (assume younger) branchlets: in whorls of 3 to 5, occasionally opposite, broad-elliptic to ovate or subcircular, to 12 mm long and 6 mm wide, with flat to revolute margins. 

Tetratheca spp. tend to produce solitary or paired flowers in leaf axils, well beyond the foliage. They typically have 4 petals which resemble an even cross (some flowers can have 5 petals), with 8 stamens and 1 carpel. Flowers often point downwards (pendent) which attracts certain insects. In this species, flowers are solitary or paired, deep lilac-pink, to about 20 mm across, occurring mostly in July to October.

Tetratheca spp. produce fruit as capsules which open longitudinally. In this species, the capsules are to 5 mm long and opening longitudinally; seeds about 3 mm long.

In the garden

This species is known to be cultivated but not a lot of information is available (especially online). 

It is a nice plant and very showy when in flower. It grows on moister sandy soils in sunny environments, so may need similar conditions in a garden.

Check with native nurseries for availability. 

Some Tetratheca spp. are cultivated commonly, especially T. thymifolia and they make very attractive additions to gardens.

Plant them along open borders or in rockeries for best affect, with well-drained soils and some shade during the warmer months.


Propagation can be carried out from seed but this is rarely available. Cuttings of hardened, current season’s growth usually strike fairly readily. The use of a root-promoting hormone seems advantageous.

Other information

Tetratheca comprises around 50 to 60 species, endemic to Australia. They occur in all states with the exception of the Northern Territory. NSW currently has 16 species.

The flower colours have given rise to the common name for many species of “Black-eyed Susan”. However, note that this common name also applies to several exotic species.

Most Tetratheca spp. would die in a fire and regenerate from the seed bank.

Tetratheca – Ancient Greek – tetra meaning “four”, and theke meaning “sac or box”, relating to the condition of the stamens in the flowers which have four lobes or cells.

shiressiihonours David William Campbell Shiress (c. 1862-1944) – a friend of botanist W. F. Blakely and who went on many collecting trips with him. He collected a lot of botanical specimens around Sydney in the 1920s. 

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

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

Plants of South Eastern Australia (LUCID Online Plant Identification webpage / app) – Tetratheca shiressii profile page https://apps.lucidcentral.org/plants_se_nsw/text/entities/tetratheca_shiressii.htm

The Family Tremandraceae – APS NSW                https://austplants.com.au/resources/Documents/South-East-Documents/Articles_About_Plants_and_Gardens/The_Family_Tremandraceae_John_Knight.pdf

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 Dan Clarke and Jeff Howes.