A lilly-pilly tree, potentially reaching 30 metres in its native habitat, it is found in riverine rainforest, often close to streams, on the North Coast of NSW (north from and as far west as the Hunter Valley) extending along the coast into far northern Queensland (to around Cairns). This is only one species in NSW.
The leaves are opposite and glossy-green, with the lower surface much paler, ranging from lanceolate to narrow-elliptic, to about 16 cm long and 5 cm wide, with a pointy (acuminate) tip. The oil glands are numerous and fine and can be seen with a hand lens. The leaves have wavy (undulate) margins.
The flowers are produced in large numbers in panicles, beyond the leaves.
The staminate flowers are cream-coloured, about 5 mm across long with stamens up to 7 mm or more long.
The fruit of Waterhousea is a berry. In this species, it is globe-shaped to about 20 mm diameter, green – turning red at maturity.
A hardy tree. It lends to rainforest themes and shady gardens. It can be grown as a hedge if kept well maintained. It may be slow growing. Will be long-lived if growing in suitable conditions.
Give some supplementary water, especially in hot dry conditions. Full sun to part shade. Likes an enriched soil but ensure good drainage.
Prune to encourage a desired shape and denser foliage. They can get leggy with gaps in the foliage if not pruned.
Attractive to birds. Likes a well-drained soil with some enrichment. Reported to tolerate light frost and cool climates.
Flowers and fruits more prolifically after pruning.
This species can be attacked by psyllid (a sap sucking insect). Use a white oil to control serious infestations.
May be susceptible to Myrtle Rust.
Propagation from seed or soft-wood cuttings of current season’s growth.
Several cultivars are available:
‘ST1’ Whisper, with pink new growth
‘Amaroo’ with bronze new growth.
‘Sweeper’ with strongly undulate foliage.
This species was originally named Syzygium floribundum but changed to Waterhousea in 1983. It is considered by some botanists to be Syzygium but the name of Waterhousea is currently retained by NSW Herbarium.
Lives in habitat unlikely to burn. Likely killed by fire but may be able to produce suckering and epicormic growth.
Waterhousea – Named in Honour of John T. Waterhouse (1924-1983), a botanist and lecturer at the University of NSW and a substantial contributor to research and collecting of Australian flora. The genus was named after him just before he died.
floribundum – Latin for abundance of flowers, referring to the many-flowered panicles.
Not considered at risk in the wild.