Weedy discovery on the North Shore a first for New Zealand

5 November 2009

A nasty weed never seen in New Zealand before has been found on the North Shore by a member of a new weedspotting network.

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The Auckland Regional Council (ARC) launched their Weedspotters initiative in June this year to encourage people in the community to be on the look out for new and emerging weed species and it has already paid off.

A North Shore ‘spotter’ has reported an infestation of knotweed in Glenfield that has been identified by Landcare Research in Lincoln as Persicaria chinensis, or Chinese knotweed. This weed has never before been recorded in New Zealand.

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“This is a really good example of how people in the community can help us fight weeds,” says Vivienne Lepper, ARC Biosecurity Officer.

“If we know where a weed is, we can do something about it. Chinese knotweed is a known pest plant in the Pacific and we want to stop it spreading any further here.”

“MAF Biosecurity New Zealand (MAFBNZ) has no records of it being imported and Landcare Research has no records of this plant ever being in New Zealand prior to this discovery so it’s a new threat to deal with,” says Vivienne.

“ARC will be working in partnership with MAFBNZ to ensure this invasive plant is carefully managed. A response plan for the weed is currently being prepared.

“Its long horizontal stems grow deep and wide underground which help it spread so vigorously. Like other knotweeds, it can form dense stands that shade and crowd out other vegetation, and displace native species.

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“We are treating it as a Total Control Pest Plant. We have already started an eradication project on the site where it was found in Glenfield and are working with the residents there.

“We urge people to call us if they think they have Chinese knotweed on their property, rather than trying to control it themselves. As a Total Control Pest Plant we will do the work at no cost to the landowner.

“It’s most likely spread through fragments breaking off and re-sprouting into new plants so people treating it themselves could accidentally spread it further.”

The plant is related to other invasive knotweeds found in New Zealand such as Reynoutria japonica (Japanese knotweed) and Reynoutria sachalinensis (giant knotweed).

It is commonly known as Chinese knotweed, liane rouge, red bush or huo tan mu.

For more information or to report suspected sightings contact the ARC on 09 366 2000, 0800 80 60 40 or biosecurity@arc.govt.nz

ENDS

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