Calothamnus rupestris is a medium, erect shrub, potentially reaching 4 metres tall (often found much smaller), spreading to several metres wide.
It is endemic to Western Australia, growing along the west coast, from around Bridgetown and Margaret River, to mostly around Bullsbrook, as far east as around Brookton.
It is found on granite outcrops and rocly areas in heathland and shrubland as well as dry sclerophyll woodland.
Calothamnus have simple and alternate to opposite or whorled leaves (generally very crowded along stems). In this species, they are to 25 mm long, very narrow to about 2 mm wide, circular in cross section and prickly; dark green in colour.
Calothamnus have flowers arranged in cymose-inflorescences, usually emerging from leaf axils and some times clustered into compound-groups. Flowers are 4 or 5-merous with petals sitting ontop of sepals and with many emerging stamens all connected in ‘staminal claws’ surrounding one carpel. In this species, flowers have 4 petals and sepals (fused together), are to around 8 mm wide with 4 staminal claws to 4 cm long; deep pink-red in colour, emerging in clusters in leaf axils; often developing on one side of the stem and appearing from winter to summer.
The fruit is a capsule, hairy, about 8 mm across, with two prominent lobes; the lobes resembling ‘mouse ears’.
Author’s notes: Calothamnus rupestris is a medium, erect shrub that has reached a height of two metres with a similar spread in our cold-climate garden (near Armidale). It attracts honeyeaters and is a very pretty plant. Best grown on a well-draining soil in part-shade for best results. It may not tolerate humid and overly-shady areas too well.
Perhaps the Cliff Net Bush is best grown away from paths as the foliage is a trifle prickly.
It is a plant well-known in cultivation – well worth sourcing. The flowers are quite large and conspicuous.
Propagate all species from seed or cuttings. Roots are produced rapidly from cuttings. Cutting-grown plants flower much sooner than seed-grown plants.
Calothamnus rupestris is known as the Cliff Net Bush or Mouse Ears. Net Bush is the common name applied to most Calothamnus.
This species likely regenerates from soil-stored seed or seed released from capsules after fire. Reportedly, new plants take seven years to produce seed.
Calothamnus is a genus of about 41 species, all endemic to Western Australia, and generally, found in the south-west of Western Australia.
Calothamnus – From the Ancient Greek – Kallos (κάλλος) – meaning “beautiful” and thamnos (θάμνος) a “shrub” or “bush”. This is a very apt name for this group of beautiful Western Australian shrubs.
rupestris – Latin meaning ‘rocks’ or ‘near rocks’ – describing the habitat of the species.
This species is not considered to be at risk of extinction in the wild. Although – more frequent fire events may severely affect its recruitment in the wild.
Western Australian Herbarium. Florabase—the Western Australian Flora – Calothamnus rupestris profile page https://florabase.dbca.wa.gov.au/browse/profile/5428
Wrigley, J.W. & Fagg, M.I. (2001). Australian Native Plants – Propagation, cultivation and use in landscaping. 4th edition. New Holland Publishers, Pty. Ltd. Australia.
Wikipedia – Calothamnus rupestris profile page https://en.wikipedia.org/wiki/Calothamnus_rupestris