Hibiscus is a genus which is well known in horticulture through the many exotic species and cultivars, principally Hibiscus rosa-sinensis which has thousands of registered cultivars. Overall there are more than 300 Hibiscus species which occur mainly in tropical and sub-tropical regions. Australia has about 40 native species, most of which are endemic. There are also a number of closely related genera in Australia with Hibiscus-like flowers. These include Abelmoschus, Alyogyne, Gossypium, Howittia and Lagunaria.
Hibiscus trionum is a small shrubby annual or perennial to about 1 metre high by a similar width. The leaves are up to 70 mm long by 20-50 mm wide and may be oval shaped or lobed with toothed margins. The flowers are white or pale pink with a central maroon blotch. They are about 60 mm in diameter of typical hibiscus shape. In common with most Hibiscus species, the individual flowers last only 1-2 days but new flowers continue to open over a long period, generally in summer and autumn. The flowers are followed by hairy seed capsules containing a number of seeds.
H.trionum is an easily grown species for a wide range of climates. It prefers a sunny position with reasonably well drained soils. It can tend to self sow in cultivation and may be slightly weedy but is easily kept in check and is rarely a serious nuisance. Northern forms are frost sensitive.
In common with the exotic hibiscus cultivars, hibiscus beetles may be a problem. These can be controlled by placing white ice cream containers with detergent water among the hibiscus plants and putting fresh water and detergent in the containers every few days.
Propagation from seed is relatively easy and no special pretreatment is needed. Cuttings also strike readily.
For further information on Australian Malvaceae, see the Australian Native Hibiscus and Hibiscus-like Species website.
Thanks to Jim Purdie for the hint on using detergent water to trap hibiscus beetles.
Photo: Geoff Keena