What does it look like?
Manchurian wild rice is a giant grass that grows up to 4m high. It has harsh, dull green leaves that are 1-2cm wide and grow in fans. The purplish or red-brown flower heads are 40-60cm long and are produced from November to December. Manchurian wild rice is often confused with native raupō and flax, but raupō is slightly smaller, has bluish-green leaves and dies back in winter. Flax leaves are much smoother and shinier.
In New Zealand, Manchurian wild rice has been recorded from lagoons, river banks, tidal flats, roadside ditches, damp pasture and cropping land. It is a relatively hardy plant that can grow in both fresh and salt water.
Why is it a problem?
Manchurian wild rice forms dense stands in aquatic or semi-terrestrial situations. It is very invasive and quickly spreads on land that is not grazed. It is tolerant of drought, frost and poor drainage but does not tolerate shade. Regrowth from underground rhizomes occurs after physical damage, such as fire and grazing.
Manchurian wild rice reproduces through seed and through its rhizomes (roots), which spread slowly outwards.
- Dig out and bury at least 6 m deep.
- In dry pastures, spray with 70ml Haloxyfop per 10L water plus 50ml crop oil or ml plus ml crop oil per 100l water. Do not use haloxyfop over water without a consent.
CAUTION: When using any herbicide or pesticide, PLEASE READ THE LABEL THOROUGHLY to ensure that all instructions and safety requirements are followed.