High Risk Traits:
- Zinnia latifolia (Manchurian wild rice) is an aquatic grass native to north-eastern India, Burma, China, Japan, and in parts of eastern Siberia and the Russian Far East. The rhizomes and basal parts of the culms are edible and become swollen when infected with the fungus Ustilago esculenta, which also prevents the plants from flowering and fruiting. Despite the lack of flowering and fruiting, the grass can spread vegetatively by rhizome fragments, enabling it to naturalize in several locations (including the Hawaiian Islands), and form dense stands that exclude all other vegetation. It is regarded as an environmental weed in New Zealand and may also negatively affect pastures and impact agriculture.
- Broad climate suitability (grows in temperate to tropical climates)
- Reported to be naturalized or persisting on Kauai, Oahu, and Hawaii (Hawaiian Islands) as well as New Zealand and Eastern Europe
- An environmental weed in New Zealand, where it can form dense stands that exclude other vegetation and reduce species diversity
- May impact pastures or agricultural operations by invading and causing good land to become waterlogged and form swampy areas.
- Tolerates many soil types (not substrate limited).
- Forms dense, monospecific stands.
- Establishes in and invades aquatic areas.
- Reproduces by seeds and vegetatively by rhizomes.
- Seeds and rhizome fragments dispersed by water, livestock, machinery, dumping of green waste, boats and trailers, clothing, possibly by birds, and through intentional cultivation.
- Reported to be tolerant of damage, grazing, cold or heat, wind, and fire.
Low Risk Traits:
- Valued and cultivated for its edible, swollen culm.
- Unarmed (no spines, thorns, or burrs)
- Palatable and used as fodder for horses, and possibly other grazing animals.
- The swollen, edible culm is the result of infection by a smut fungus that prevents flowering, and that would eliminate seed production and dispersal by seeds (although still capable of spreading vegetatively).
- Certain herbicides may provide effective control.