Hoya is a genus of around 200 species with seven occurring in Australia. They are climbing plants with succulent foliage and the genus is popular in horticulture with numerous forms and cultivars being grown by enthusiasts. H.australis is the most widespread and the most commonly grown of the Australian species while H.macgillivrayii is probably the most spectacular
Hoya macgillivrayii is a moderately vigorous climbing species. The leaves are ovate or linear-lanceolate in shape and about 15 cm long. The stems contain a white, milky sap. The fragrant, red to purple flowers are waxy and occur in clusters of about 4 to 15, each on a long pedicel (stalk), and each flower is about 50 mm in diameter. The flowers are usually seen in spring and early summer and are borne on the same stalk in successive seasons. The seed pods are long and slender, about 150 to 250 mm long containing a number of seeds.
The species is popular in cultivation in tropical and subtropical areas. In cooler climates a heated glasshouse may be needed for successful cultivation. Good drainage is essential. H.macgillivrayii is also suited to growing in containers and hanging baskets as it seems tolerant of root constraint. Flowering is best if good light is available.
H.macgillivrayii can be grown from fresh seed, which requires no pretreatment. Cuttings also strike readily
Hoya macgillivrayii with a cluster of Hoya australis flowers on the right
Photo: Keith Townsend