Zizania latifolia
NPPA pest plant
Environmental Weed (2024)
Common names
Manchurian rice grass
Biostatus
Exotic
Category
Vascular
Structural class
Grasses
Simplified description
Large growing marginal emergent grass with light (dull) green, coarse, long straight leaves growing in fans, and purplish - red/brown flowers.
Flower colours
Green, Violet/Purple
Detailed description
Tall marginal perennial. Tufts coarse, 2–4 m tall. Rhizomes stout, spreading. Leaves light green, up to 1 m or more long and 1–2 cm wide, with a stout midrib, papery, harsh, dull greygreen, tapering to a point, rustling loudly in wind. Ligule a very dense fringe of hairs. Inflorescense purplish or reddish brown, 20–40 cm long, dense and soft to touch; lower part is spreading and male; upper part is more closed and with female flowers.
Similar taxa
Raupō (Typha orientalis). Raupō is usually shorter (1–3 m) than Manchurian wild rice, with bluish-green leaves with a characteristic twist in the leaf blade and a cylindrical brown flower spike.
Distribution
Locally naturalised Northland, Auckland, Waikato and Wellington, abundant on the margins of Northern Wairoa River, Northland.
Habitat
Lowland still and slow flowing water bodies (both resh water or moderately saline).
Conservation status
Not applicable
Detailed taxonomy
Family
Ecology
Flowering
November, December
Fruiting
Autumn
Year naturalised
1906
Origin
Eastern Asia
Reason for introduction
Accidental, contamination of ballast
Tolerances
Tolerant of drought and frost; highly tolerant of poor drainage and intolerant of shade. Regrowth from underground rhizomes occurs after physical damage, fire and grazing.
Control techniques
Notify Ministry for Primary Industries if found.
Life cycle and dispersal
Perennial. Plants are hermaphroditic with the female inflorescence borne above the male inflorescence. Large amounts of seed is produced which germinated quickly. Reproduces through seed or vegetatively through tailoring and rhizome extension. Rhizomes spread slowly outwards. Seeds and rhizome fragments spread via water, livestock, machinery, e.g. graders, dumping of green waste, eel nets, boats and trailers, clothing and possibly by birds.
Wetland plant indicator status rating
Information derived from the revised national wetland plant list prepared to assist councils in delineating and monitoring wetlands (Clarkson et al., 2021 Manaaki Whenua – Landcare Research Contract Report LC3975 for Hawke’s Bay Regional Council). The national plant list categorises plants by the extent to which they are found in wetlands and not ‘drylands’. The indicator status ratings are OBL (obligate wetland), FACW (facultative wetland), FAC (facultative), FACU (facultative upland), and UPL (obligate upland). If you have suggestions for the Wetland Indicator Status Rating, please contact: [Enable JavaScript to view protected content]
OBL: Obligate Wetland
Almost always is a hydrophyte, rarely in uplands (non-wetlands).
Other information
National Pest Plant Accord species
This plant is listed in the 2020 National Pest Plant Accord. The National Pest Plant Accord (NPPA) is an agreement to prevent the sale and/or distribution of specified pest plants where either formal or casual horticultural trade is the most significant way of spreading the plant in New Zealand. For up to date information and an electronic copy of the 2020 Pest Plant Accord manual (including plant information and images) visit the MPI website.
Environmental Weed (2024)
This plant is named in a list of 386 environmental weeds in New Zealand 2024 prepared by DOC. 759 candidate species were considered for inclusion on this new comprehensive list of environmental weeds in New Zealand. The species considered were drawn from published lists of weed species, lists of plants that must be reported or managed by law if observed, existing national and regional programmes and agreements for pest management, and species already managed by the Department of Conservation (DOC). Candidate species were then assessed to see if they were fully naturalised and whether they have more than minor impacts in natural ecosystems. Read the full report here.
NVS code
The National Vegetation Survey (NVS) Databank is a physical archive and electronic databank containing records of over 94,000 vegetation survey plots - including data from over 19,000 permanent plots. NVS maintains a standard set of species code abbreviations that correspond to standard scientific plant names from the Ngä Tipu o Aotearoa - New Zealand Plants database.
ZIZLAT
Referencing and citations
References and further reading
Champion P. et al. 2020. Freshwater Invasive Species of New Zealand 2020. NIWA publication. https://docs.niwa.co.nz/library/public/FreInSpec.pdf
Johnson PN, Brooke PA. 1989. Wetland plants in New Zealand. DSIR Field Guide, DSIR Publishing, Wellington, NZ. 319 p.
Attribution
Factsheet prepared by Paul Champion and Deborah Hofstra (NIWA).