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Waikato River enhancement - Herbicide spraying (yellow flag iris)

"Tooku awa koiora me oona pikonga he kura tangihia o te maataamuri." "The river of life, each curve more beautiful than the last."


Along the banks of the lower Waikato River, the pest plant yellow flag iris has infested the land, choking our native plants and damaging the river’s ecosystem.

Yellow flag iris is a 'Total Control' plant in the Waikato Regional Pest Management Strategy, meaning all land occupiers are responsible for destroying yellow flag iris on their property.

Environment Waikato advises under the Waikato Regional Plan Permitted Activity Rule “Wide spread application of agrichemicals” its intention to undertake a herbicide spray programme on a 2.5 kilometre stretch of the eastern Waikato River margin south of Tainui Bridge Road.

This is a land based programme targeting nuisance vegetation such as yellow flag iris, willow and alder that is causing or is likely to cause waterway and land management problems on Environment Waikato managed land. 

This is the first works site targeting the toxic yellow flag iris and other plant pests on Environment Waikato managed flood protection land along the Waikato River.

Spraying is scheduled to begin March 2011 and repeat applications may be carried out over a three month period.  Spraying is weather and river level dependent but, may be carried out during daylight hours any day of the week.  Property owners adjoining the land to be sprayed have been notified via mail.

From Huntly downstream to Mercer, pest plant control work will progress on Environment Waikato managed land.  Much of the treated area will be replanted with native species to help re-establish native river margin habitat and improve the health of the river.


Media releases

17, December 2010: Yellow flag iris spraying project due to start in February 2011


More information

For more information on the Waikato River Enhancement project contact Louisa Alix 0800 800 401 or Ian Wallace at Waikato Rivercare 07 857 0206.