An evergreen shrub of trailing or climbing woody stems to c. 3 m tall, shoots and younger branches with a sometimes dense covering of silky pubescence. Petiole 1.5 cm, leaves +/– flattened, leathery, oblong to elliptic to obovate, 4–9 cm x 1.5–3.5 cm with entire margins or very shallowly toothed in the upper leaf blade, tip rounded to acuminate, blades narrowing at the base. Flowers are borne terminally and solitary, subsessile, with green sepals covered in silky pubescence, petals yellow, 1.5–2.5 cm long, obovate to obovate-oblong, with a shallow notch along the top. Stamens numerous, free, staminodes absent. 5–8 carpels, glabrous.
Distribution Australia Occurring in a belt along the entire eastern coast, from northern Queensland to southern New South Wales and possibly just into Victoria. Concentrated close to the coast but recorded up to c. 150 km inland in New South Wales.
USDA Hardiness Zone 9a-9b
RHS Hardiness Rating H3
Awards RHS Award of Garden Merit
Conservation status Not evaluated (NE)
H. scandens was first described in 1799 within the genus Dillenia. According to Loudon (Loudon 1824), however, it had already been in cultivation in Britain since 1790 under the name H. volubilis, which has since been sunk into synonymy. It is unclear whether it has been in continuous cultivation here since then, or whether it has come and gone several times before becoming more firmly established as an excellent climbing plant in the mildest, southern gardens or else under glass, earning itself an RHS Award of Garden Merit.
The plant is widely cultivated in its native Australia, and the same is true of other parts of the world with a warm-temperate, Mediterranean or subtropical climate, where it can be very vigorous and drought tolerant, such as parts of New Zealand, California, Mediterranean Europe and the like. However, in spite of its relative abundance in the horticultural trade generally, there are scant references to its cultivation outside these climatic zones.
In 2018, it was listed for sale by four UK nurseries, according to the RHS Plant Finder, three of these in Cornwall, where it is reported to thrive outdoors along the southern coast, including locations around Falmouth, at Lamorran House, and on the tidal island of St Michael’s Mount where it is impervious to salt-spray (Clough & McMillan Browse 2004).
As an evergreen with large handsome flowers 5–6 cm in diameter it can be very ornamental and is useful for scrambling over walls, as it does at Tregrehan, Cornwall (J. Grimshaw pers. comm. 2018). It is easily propagated by cuttings, as it has been at the Royal Botanic Garden Edinburgh where it grows in the Temperate Lands glasshouse. It does best here when given plenty of light and some sun, and has previously reached 2–3 m tall (D. Tricker pers. comm. 2018).