Tetratheca rupicola

Pink-eyes, Black-eyed Susan

Family: Elaeocarpaceae

A shrub usually to 0.4 m high, spreading to about the same width. 

It is endemic to NSW, growing on the central tablelands / central coast divide; from as far north as Newnes State Forest, and south and east towards Kurrajong and most of the Blue Mountains (down to Blaxland), through the west of Lake Burragorang then around Robertson, Fitzroy Falls and Avon Dam (Note: it has a very similar distribution to T. rubioides, and also appears similar to this species. Hence, some records may be erroneous).

It is found in dry sclerophyll woodland and forest as well as rocky heathland, on sandstone substrate. 

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 usually in whorls of 4 to 6; sometimes appearing in pairs of alternate or opposite leaves, or in whorls of 3 at the base of branches; to 15 mm long and 1.5 mm wide; linear with margins rolled down. 

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, deep lilac-pink, to about 20 mm across, occurring mostly in October to December.

Tetratheca spp. produce fruit as capsules which open longitudinally. In this species, the capsules are to 7 mm long, ovate to oblong and beaked, and opening longitudinally; seeds about 4 mm long.

In the garden

Not a lot of information is currently available.

Cultivation information for this species is very scant. Check with native nurseries for availability. It is one of the rarer species in NSW and so may not be commonly cultivated. 

It grows naturally on shallow, well-drained soils derived from sandstone, so consider similar conditions when planting in a garden. 

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

This species is very similar to T. ericoides, T. neglecta and T. rubioides and intermediates may occur. 

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.

rupicola – derived from Latin – named for its habitat which means “living near or on rocks”.

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

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

Plants of South Eastern Australia (LUCID Online Plant Identification website/app) – Tetratheca rupicola profile page: https://apps.lucidcentral.org/plants_se_nsw/text/entities/tetratheca_rupicola.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

By Dan Clarke and Jeff Howes.