The ORC’s Environmental Data Portal is experiencing high traffic volumes affecting its effectiveness at present. The site is being worked on at present and people are asked to be patient. Please be considerate in using this tool, some people require access to the EDP for important decision-making today.
Environmental Data PortalThe ORC’s Environmental Data Portal is experiencing high traffic volumes affecting its effectiveness at present. The site is being worked on at present and people are asked to be patient. Please be considerate in using this tool, some people require access to the EDP for important decision-making today.
Common name: | Yellow Flag Iris |
Scientific name: | Iris pseudacorus |
Management programme: | Unwanted organism |
If you have seen or suspect the presence of this pest you must report the sighting to us.
Contact Otago Regional Council on 0800 474 082 or biosecurity@orc.govt.nz
Yellow Flag Iris is a highly invasive plant that forms dense stands in wetland areas, lakeshores, rivers, and streams. It outcompetes native species, disrupts water flow, and alters the natural structure of waterways. The plant can invade pastures, displace native vegetation, and is toxic to livestock. Its seeds are buoyant, easily dispersed by water, and can remain viable for over a year, making the plant difficult to control once established. Yellow Flag Iris negatively impacts the ecological health of water bodies, cultural values, and agricultural productivity.
Yellow Flag Iris is found across Otago, including Mosgiel, Lake Wānaka, Lake Whakatipu, Lake Hayes, Tahakopa Estuary in Papatowai, and Oamaru.
It is an offence to breed, knowingly communicate, exhibit, multiply, propagate, release, or sell, an unwanted organism (Biosecurity Act 1993).
Dig out.
Plant parts requiring disposal: seeds and rhizomes.
Contact your local council for appropriate disposal locations.
No qualifications: Foliar spray with 100ml glyphosate per 10L of water.
Certified handler/experienced agrichemical user: Foliar spray with 100ml glyphosate per 10L of water and 20ml penetrant.
Caution: When using any herbicide or pesticide please read the label thoroughly to ensure that all instructions and safety requirements are followed.
Biological control is currently not available for this species.
You must notify the Otago Regional Council if you suspect the presence of this organism.
If you think you've seen Yellow Flag Iris:
An unwanted organism is not managed under the ORC Pest Plan but may be controlled as part of our Biosecurity Strategy.
Any plant listed on the NPPA is an unwanted organism under the Biosecurity Act 1993. This means they cannot be distributed or sold in New Zealand.