Chinese violet (Asystasia gangetica subsp. micrantha)

Profile

Impact

Chinese violet is a rapidly growing perennial creeper.  It is a potentially serious environmental and agricultural weed in Australia as it can completely smother other vegetation, removing habitat, and reducing biodiversity and productivity. This weed grows in tropical and subtropical areas and threatens biodiversity in these areas.

Distribution

Chinese violet is native to India, the Malay Peninsula and Africa. It is a major weed overseas, notably in Malaysia, Indonesia and the Pacific islands, where it infests crops such as rubber and coffee, but particularly palm oil plantations.

The subspecies has become invasive in Australia, with its first recording as naturalised made in New South Wales (NSW), at Boat Harbour north of Newcastle in 1999. It is now known to occur in a number of nearby locations, and was found at South West Rocks near Kempsey on the NSW Mid North coast in 2009. These infestations are currently subject to an eradication program and there are no other infestations currently known in NSW.

Distribution map

Spread

Chinese violet plants spread by seed and plant fragments and can flower and fruit year round.

The seeds are dispersed explosively from the drying fruit capsules. After most of the ripe capsules have released their seeds, the plant dies back to ground level. Winter frosts kill above-ground plant parts but plants regrow the following spring from their basal shoots.

Trailing stems can take root at each node when they come into contact with moist soil. Most infestations in Australia have occurred as a result of dumping garden waste or uncontrolled garden plantings growing into nearby areas.

Description

Chinese violet grows in sprawling mats, it grows to 1 m high, but can grow over vegetation up to 3 m tall.

Key identification features

  • Leaves and stems have scattered hairs. Leaves are paler beneath and occur in pairs on stems. The leaves are oval shaped, sometimes almost triangular, 2.5 – 16.5 cm long and 0.5 – 5.5 cm wide.
  • White bell-shaped flowers are 2 – 2.5 cm long, with characteristic purple blotches in two parallel lines inside.
  • Fruit capsules are 3 cm long, guitar-shaped (with the neck of guitar attached to stem) and contain four flattened seeds held in place by conspicuous hooks.

Another commonly cultivated subspecies of Chinese violet (Asystasia gangetica subspecies gangetica), is planted widely in Australia but is less weedy. This subspecies has purple flowers and is naturalised in North Queensland and in the Northern Territory.

Habitat

Chinese violet infestations in Australia have all occurred on coastal sandy soils, but the plant is thought to tolerate a wide range of soil types, preferring full sun or part shade. Plants become spindly in deep shade.

Acknowledgements

Written by Peter Gorham and John Hosking 2003; 2012 edition reviewed by Rod Ensbey; Edited and prepared by Elissa van Oosterhout and Birgitte Verbeek.

References

CRC for Australian Weed Management (2003). Chinese violet Weed Management Guide. CRC for Australian Weed Management, Adelaide, South Australia. 

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Control

Your local council weeds officer will assist with identification, control information and removal of this weed. Infestations can be spread by inappropriate control activities. New infestations can develop from any rhizomes that are moved or dropped during control activities. Early detection and eradication will prevent the spread of this weed.

Herbicide options

WARNING - ALWAYS READ THE LABEL
Users of agricultural or veterinary chemical products must always read the label and any permit, before using the product, and strictly comply with the directions on the label and the conditions of any permit. Users are not absolved from compliance with the directions on the label or the conditions of the permit by reason of any statement made or not made in this information. To view permits or product labels go to the Australian Pesticides and Veterinary Medicines Authority website www.apvma.gov.au

See Using herbicides for more information.


PERMIT 13678 Expires 30/09/2017
MCPA 340 g/L + Dicamba 80 g/L (Kamba® M)
Rate: 100 mL per 15 L of water per 150 sq. m. (1 L /10 m2)
Comments: Spot spray application. Apply to actively growing weeds before seed set on the plants.
Withholding period: 7 days.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate


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Biosecurity duty

The content provided here is for information purposes only and is taken from the Biosecurity Act 2015 and its subordinate legislation, and the Regional Strategic Weed Management Plans (published by each Local Land Services region in NSW). It describes the state and regional priorities for weeds in New South Wales, Australia.

Area Duty
All of NSW General Biosecurity Duty
All plants are regulated with a general biosecurity duty to prevent, eliminate or minimise any biosecurity risk they may pose. Any person who deals with any plant, who knows (or ought to know) of any biosecurity risk, has a duty to ensure the risk is prevented, eliminated or minimised, so far as is reasonably practicable.
Greater Sydney Regional Recommended Measure*
Land managers should mitigate the risk of new weeds being introduced to their land. The plant should be eradicated from the land and the land kept free of the plant. The plant should not be bought, sold, grown, carried or released into the environment. Notify local control authority if found.
Hunter Regional Recommended Measure*
Land managers should mitigate the risk of new weeds being introduced to their land. The plant should be eradicated from the land and the land kept free of the plant. The plant should not be bought, sold, grown, carried or released into the environment. Notify local control authority if found.
Murray Regional Recommended Measure*
Land managers should mitigate the risk of new weeds being introduced to their land. The plant should be eradicated from the land and the land kept free of the plant. The plant should not be bought, sold, grown, carried or released into the environment. Notify local control authority if found.
North Coast Regional Recommended Measure*
Land managers should mitigate the risk of new weeds being introduced to their land. The plant should be eradicated from the land and the land kept free of the plant. The plant should not be bought, sold, grown, carried or released into the environment. Notify local control authority if found.
North West Regional Recommended Measure*
Land managers should mitigate the risk of new weeds being introduced to their land. The plant should be eradicated from the land and the land kept free of the plant. The plant should not be bought, sold, grown, carried or released into the environment. Notify local control authority if found.
Riverina Regional Recommended Measure*
Land managers should mitigate the risk of new weeds being introduced to their land. The plant should be eradicated from the land and the land kept free of the plant. The plant should not be bought, sold, grown, carried or released into the environment. Notify local control authority if found.
*To see the Regional Strategic Weeds Management Plans containing demonstrated outcomes that fulfill the general biosecurity duty for this weed click here

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Reviewed 2017