What Does It Look Like?
What is it?
Wild Rice (Zizania spp.) is an annual or perennial aquatic grass rooted in the substrate, some species with rhizomes or stolons (spreading lateral stems), and with separate male and female flowers on each plant. Stems are upright growing to 5 m high and either emergent or floating. Leaves may be concentrated on the lower portion of the stem or evenly distributed. Leaf sheaths (lower parts of the leaf that envelop the stem) are open, and ligules (the structures between the leaf sheath and the blade) are membranous, or thin and dry, and hairless. Leaf blades are flat, aerial or floating, rough or smooth growing to 1.5 m long (Terrell 2007). Flower heads are branched, up to 120 cm long and occur at the end of stems. Branches are usually unisexual, lower branches with stalked male flowers, upper branches with stalked female flowers and middle branches sometimes with both male and female flowers. Flowers are white to purple to brown. Seed is cylindrical to 30 mm long (Terrell 2007). Species include the annual plants, Southern Wild Rice (Zizania aquatica) and Northern Wild Rice (Z. palustris) and perennials, Texas Wild Rice (Z. texana), and Manchurian Wild Rice (Z. latifolia), known also as Asian Wild Rice and Water Bamboo (Clayton et al. 2006).
Manchurian Wild Rice occurs as a weed in New Zealand and is described as a dense, mat-forming perennial to 2–3 m with rhizomes (spreading lateral underground stems) up to 5 m long and fibrous roots. Harsh, papery, dull grey-green leaves (2–3 cm wide) which are straight, up to 2.5 m long, have a stout midrib, taper to a point, and rustle loudly in the wind. From November to December a purplish or red-brown flowerhead (40–60 cm long) is produced with large numbers of seeds in some seasons (Weedbusters New Zealand 2004; Auckland Regional Council 2007).
For further information and assistance with identification of Wild Rice, contact the herbarium in your state or territory.
Flower colour
White, Purple, Brown
Growth form (weed type/habit)
Grass, Aquatic
Where it currently grows? Preferred habitat
In its native range, Manchurian Wild Rice (Z. latifolia) grows in the shallow waters of lakes and swamps, forming large patches (Terrell 2007). In New Zealand, Manchurian Wild Rice occurs in fresh or moderately saline water bodies and margins, wetlands, damp ground, fernland and adjacent pasture. It tolerates a wide range of conditions including cold or heat, wind, fire, different soil types, moderate shade, moderate salinity and the effects of grazing (Weedbusters New Zealand 2004; Auckland Regional Council 2007).
Southern Wild Rice (Z. aquatica) grows in fresh or somewhat brackish marshes, swamps, tidal mud flats, streams, and lakes. Northern Wild Rice (Z. palustris) grows on muddy shores and in shallow water of lakes and streams, often forming extensive stands (Terrell 2007).
Are there similar species?
Manchurian Wild Rice looks similar to New Zealand Raupo (Bullrush: Typha orientalis), but Manchurian Wild Rice is taller (2–3 m compared to 1–2 m for Raupo). Also, Raupo leaves are thick and spongy, have no midrib, and twist upwards, whereas Manchurian Wild Rice leaves are dry and papery, usually upright and may bend at top without twisting. It also looks similar to New Zealand Flax (Phormium spp.), but Flax leaves are much wider, smoother, thicker and shinier than those of Wild Rice (Weedbusters New Zealand 2004; Auckland Regional Council 2007).