Click on images to enlarge
infestation (Photo: Trevor James)
infestation (Photo: Sheldon Navie)
habit (Photo: Sheldon Navie)
large strap-like leaves (Photo: Trevor James)
close-up of leaves (Photo: Sheldon Navie)
stems and flowers (Photo: Sheldon Navie)
flowers (Photo: Trevor James)
close-up of flower from above (Photo: Sheldon Navie)
immature fruit (Photo: Rob and Fiona Richardson)
mature fruit (Photo: Rob and Fiona Richardson)
close-up of mature fruit with seeds (Photo: Rob and Fiona Richardson)
close-up of seeds (Photo: Steve Hurst at USDA PLANTS Database)
Iris pseudacorus L.
iris, pale yellow iris, paleyellow iris, water flag, yellow flag, yellow flag iris, yellow iris, yellow water iris
Native to northern Africa (i.e. Algeria and Morocco), the Madeira Islands, the Canary Islands, Europe and western Asia (i.e. Iran, Syria, Turkey, Azerbaijan and southern Russia).
Locally naturalised in southern Victoria and sparingly naturalised in south-eastern South Australia.
Naturalised overseas in New Zealand, most of the USA, Canada and southern South America (e.g. Argentina).
Yellow flag iris (Iris pseudacorus) is regarded as an environmental weed in Victoria and as a "sleeper weed" or potential environmental weed in other parts of southern Australia. It is widely cultivated as a garden ornamental and was first recorded as naturalised in Victoria in 1988. This species grows in shallow water and forms dense stands along waterways and in swamps. It thrives in temperate climates and can out-compete and replace native wetland plants.
In Victoria, yellow flag iris (Iris pseudacorus) has a relatively localised distribution, but grows in medium to large populations in these areas. It is mainly naturalised in riparian vegetation and permanent freshwater wetlands along the Yarra River in Melbourne. At some locations along the upper Yarra River, the understorey vegetation is dominated by yellow flag iris (Iris pseudacorus). It is particularly prevalent at the waterline of the main river channel and probably favoured by the comparatively stable water levels in this waterway.
This species may have the potential invade riparian vegetation and permanent freshwater wetlands over much of southern Australia. It appears on some local environmental weed lists in southern Victoria (e.g. in Banyule City and the The Shire of Yarra Ranges) and has been recorded in Yarra Bend Park in suburban Melbourne.
Yellow flag iris (Iris pseudacorus) is also an invasive aquatic plant in the USA, and is listed on the Global Invasive Species Database. Along the eastern seaboard, in the USA, it often invades open marsh areas and forms large colonies of almost impenetrable thickets.
Fact sheets are available from Department of Employment, Economic Development and Innovation (DEEDI) service centres and our Customer Service Centre (telephone 13 25 23). Check our website at www.biosecurity.qld.gov.au to ensure you have the latest version of this fact sheet. The control methods referred to in this fact sheet should be used in accordance with the restrictions (federal and state legislation, and local government laws) directly or indirectly related to each control method. These restrictions may prevent the use of one or more of the methods referred to, depending on individual circumstances. While every care is taken to ensure the accuracy of this information, DEEDI does not invite reliance upon it, nor accept responsibility for any loss or damage caused by actions based on it.
Copyright © 2016. All rights reserved. Identic Pty Ltd. Special edition of Environmental Weeds of Australia for Biosecurity Queensland.
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