Hypocalymma is a small genus of about 29 species, all of which occur naturally only in south Western Australia. H.angustifolium and H.cordifolium are the best known members of the genus and are widely cultivated. H.angustifolium is an erect shrub to about 1.5 metres high with narrow leaves about 25 mm long. In late winter and spring the small flowers appear along the stems with 2 or 3 flowers together at each leaf axil. The flowers are white or pink and, in some forms pale pink flowers age to a deep pink producing a dual colour effect.
This species is a very attractive and popular garden plant for a range of climates and it is readily cultivated in humid, east-coastal areas where other species from the south west are often difficult to maintain. The plant requires well drained conditions in full sun or dappled shade and it is tolerant of at least moderate frost. It should be protected from strong winds as the branches are reasonably fragile and can be damaged. Annual pruning will help maintain a dense, bushy growth habit. It is a good species for use as cut flowers.
Propagation can be carried out from seed and improved results have been reported using smoked water. Propagation from cuttings is the preferred method and cuttings strike readily from hardened, current season’s growth.
Photo: Brian Walters