Weed Alert: Chinese violet

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Chinese violet (Asystasia gangetica subspecies micrantha)

World Status | Quarantine | The Problem | Identification | Propagation | Control | Legislation

World Status

A form of Chinese Violet, Asystasia gangetica subspecies micrantha, is a major weed overseas and has begun to naturalise in Australia.

The micrantha subspecies was first recorded in NSW as naturalised at Boat Harbour, north of Newcastle, in July 1999. It is now also known from a number of nearby locations.

The commonly cultivated Chinese Violet, Asystasia gangetica subspecies gangetica, is planted widely in Australia but is less weedy. This subspecies is naturalised at Port Douglas in Queensland, and in the Northern Territory at Bartalumba Bay and Groote Eylandt.

Quarantine

All subspecies of Asystasia gangetica have been added to the list of prohibited imports and can no longer be brought into Australia.

The Problem

Asystasia gangetica subspecies micrantha is a rapidly growing perennial herb that grows to 1m high, but can grow over shrubs up to 3m tall. It can smother all vegetation in the herbaceous layer . This weed grows in tropical and subtropical areas.

Identification

Asystasia gangetica subspecies micrantha grows in mats similar to those formed by Wandering Jew, Tradescantia fluminensis.

Leaves and stems

Leaves and stems have scattered hairs. Leaves are paler below.

Flowers

20–25mm long, white outside and inside with some purple blotches in two parallel lines inside.

Fruit

30–31mm long, guitar shaped (with neck of guitar attached to stem) and containing fourflattened seeds held in place by conspicuous hooks.

Propagation

Plants spread by seed and/or rhizomes. The seeds are dispersed explosively from drying capsules but long distance dispersal is generally by man. Stems root at each node.

Control

Seedlings can be removed by hand and bagged for disposal ensuring no rhizomes are left as these can develop into new infestations.

For herbicide control, contact your Council Weeds Officer or NSW Department of Primary Industries office.

Legislation

Asystasia gangetica subspecies micrantha is a Class 1 noxious weed throughout NSW under the NSW Noxious Weeds Act 1993. This weed must be eradicated from the land and the land must be kept free of the plant. As a notifiable weed, all outbreaks must be reported to the local council.

Acknowledgements

Authors: P. Gorham, J. Hosking, NSW Department of Primary Industries