Manchurian wild rice
|Botanical Name||Zizania latifolia|
IdentificationGiant perennial rhizomatous grass growing up to three metres tall. Plants have a basal fan of leaves (up to 2cm wide) arising from bulky, far spreading rhizome systems. Plants form dense, tall stands in wet conditions at the edge of fresh water lakes, and streams. Unlike raupo, which can look similar, Manchurian wild rice does not die back in winter.
HabitatsThe edges and vicinity of fresh-water wetlands, streams and rivers, and in flood prone pastures especially around Dargaville. Small populations are known in Auckland, Waikato and Wellington., Upper photo shows Lake Kereta, on Sth Kaipara Peninsula, almost surrounded by dense infestations.
Impact to Biota and EcosystemsCauses total displacement of the natural vegetation, clogging of waterways and major problems for farmers with low-lying fields. Most often spread through rhizome fragments on contaminated machinery such as diggers.
Manchurian wild rice is a National Interest Pest. Any suspected sightings of this plant should be reported to MAF Biosecurity New Zealand on 0800 80 99 66 or to an Bay of Plenty Regional Council Pest Plant Officer. Early recognition is essential, before the plant spreads to unmanageable proportions.
To stop the spread of this pest and others, all machinery should be thoroughly cleaned and decontaminated before leaving a site.
Control of this plant will be managed by MAF Biosecurity NZ. As control is difficult, landowners should not attempt to control it themselves.
Almost certainly the most serious weed introduced into fresh water margin habitats in northern New Zealand.
This plant is prohibited from propagation, sale and distribution within New Zealand!