A spreading-scrambling woody shrub, to 3 metres tall, to several metres wide. It can form dense patches in some habitats.
It is native to Victoria, NSW and Queensland, growing as far south as around Bairnsdale in the north-east of Victoria – but then with a large disjunction in western Victoria in the Grampians (south of Horsham). It grows from around Eden in NSW, extending up the coast and coastal inland (fringe of the tablelands), potentially into Queensland as far as Moreton Bay. It was collected in South Australia but has not been seen since around 1880.
It is often found in moist / wet sclerophyll forest and rainforest edges, usually on enriched soils.
This species is the only one in the genus and it has simple and alternate leaves, to 12 cm long, and to 8 cm wide, bases often shaped like a heart (cordate) or sometimes lanceolate; hairy with toothed margins.
Flowers are produced solitarily, in leaf axils, with 5 calyx lobes and 5 petals, ranging from lavender through to violet and deep mauve, about 25 mm across and borne on long woolly stems, occurring from September to January.
The fruit is a capsule. In this species, it is rounded or globular-shaped, to 10 mm in diameter and covered with soft, silky or star-shaped (stellate) hairs. The seed capsules mature and open from December to February.
This is a plant known to be cultivated and can do really well in the right spot. It is best grown in a shady spot on an enriched soil with reliable drainage. In full sun, it does not flower well and growth becomes woody.
Ease of propagation by seed or cutting is a good reason why this shrub with violet hibiscus like flowers, should be present in a large number of home gardens.
This plant is available commercially.
Very useful to cover a fence or ugly spot. The flowers may attract butterflies and moths.
From seed or cuttings from new tip-growth about 10 cm long. This species is the only one in the genus of Howittia – endemic to Australia.
This species likely regenerates from seed after fire.
Howittia is a mono-specific (1-species) genus – endemic to Australia.
Howittia – the genus is named after Godfrey Howitt (1800-1873), a prominent Scottish doctor in Melbourne who was also a keen amateur botanist and entomologist, and who was affiliated with several scientific organisations.
trilocularis – Latin – locularis from loculus – meaning cavities or locules, and tri meaning three, referring to the three-celled fruit.
This species is not considered to be at risk of extinction in the wild.
NSW Flora Online (PlantNET) – Howittia triocularis profile page https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Howittia~trilocularis
Wrigley, J.W. & Fagg, M.I. (2001). Australian Native Plants – Propagation, cultivation and use in landscaping. 4th edition. New Holland Publishers, Pty. Ltd. Australia.
Wikipedia profile page for genus Howittia https://en.wikipedia.org/wiki/Howittia
Australian National Herbarium – Howittia trilocularis profile page https://www.anbg.gov.au/gnp/gnp7/howittia-trilocularis.html
Plants of South Eastern NSW – Howittia trilocularis profile page https://apps.lucidcentral.org/plants_se_nsw/text/entities/howittia_trilocularis.htm