Manchurian rice grass
Vascular – Exotic
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.
Large growing marginal emergent grass with light (dull) green, coarse, long straight leaves growing in fans, and purplish - red/brown flowers.
Locally naturalised Northland, Auckland, Waikato and Wellington, abundant on the margins of Northern Wairoa River, Northland.
Lowland still and slow flowing water bodies (both resh water or moderately saline).
Tall marginal perennial. Coarse tufts, 2-4m in height. Stout spreading rhizomes. Leaves light green, up to 1 m or more long and 1-2 cm wide, with a stout midrib, papery, harsh, dull greygreen, taper to point, rustle loudly in wind The ligule a very dense fringe of hairs. Inflorescenses purplish or reddish brown, 20 to 40 cm long, dense and soft to touch. Lower part is spreading and male, the upper part is more closed and with female flowers.
Raupo (Typha orientalis). Raupo is usually shorter (1-3m) than Manchurian wild rice, with bluish-green leaves with a characteristic twist in the leaf blade and a cylindrical brown flower spike.
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.
Reason for introduction
Accidental, contamination of ballast
Notify Ministry for Primary Industries if found.
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.
Factsheet prepared by Paul Champion and Deborah Hofstra (NIWA).
References and further reading
Champion et al (2012). Freshwater Pests of New Zealand. NIWA publication. http://www.niwa.co.nz/freshwater-and-estuaries/management-tools/identification-guides-and-fact-sheets/freshwater-pest-species.
Johnson PN, Brooke PA (1989). Wetland plants in New Zealand. DSIR Field Guide, DSIR Publishing, Wellington. 319pp.