Olive Hymenachne (Hymenachne amplexicaulis)
Olive hymenachne leaves and stems in ponded water
Olive hymenachne is declared a Class B (spread to be controlled) and Class C (not to be introduced to the Northern Territory) weed in accordance with the NT Weeds Management Act 2001. Olive hymenachne is also a Weed of National Significance.
- Olive Hymenachne Photo Identification Table (pdf 553Kb)
Olive hymenachne is a semi-aquatic grass which can grow up to 2.5 metres tall, above or below the water. It was originally introduced from South America to provide ponded pasture for cattle. Olive hymenachne has since demonstrated invasive characteristics, by forming dense monocultures in natural wetlands and on agricultural (predominantly sugar cane) land.
Olive hymenachne is a prolific seeder. Seeds are spread by water, including flooding events, and when transported in mud by animals and birds. Olive hymenachne can also spread vegetatively from small plant parts.
Olive hymenachne leaf detail
Small infestations are starting to develop in the NT, both in areas where it has been used in mimosa control programs as a competitive cover crop and in conservation areas, such as Kakadu National Park. The plant has considerable potential for spread within coastal and freshwater wetlands, where it could cause considerable ecological damage.
