Working Towards a Farm Scale Best Management Practice for the Eradication of the Noxious Weed Hymenachne Amplexicaulis  in Sandringham Lagoon, Mackay, Queensland

The Problem

Hymenachne amplexicaulis, native to South America, was introduced as a ponded pasture grass for cattle fodder during the dry seasons. However this plant is highly invasive invading lagoons, wetlands, rivers, creeks and table drains. It interferes with the function of irrigation, infrastructure, recreational activities and wildlife habitats. It is spread through seeds and stem fragments dispersed by water, waterbirds and contaminated stock feed.
This weed has the potential to be confused with the native Hymenachne, Hymenachne acutigluma. The difference is the exotic introduced species has a distinctive stem-clasping leaf base, where as the native Hymenachne does not. The native species is a smaller tropical species that does not grow south of Mackay.

Hymenachne amplexicaulis is a weed of national significance and is a class 2 declared weed of Queensland, meaning that it is illegal to introduce, supply, transport and keep Hymenachne amplexicaulis without a permit from Biosecurity Queensland.

Project Description

The project was designed around the needs of Sugar Cane growers, with emphasis on delivery of management strategies that individual farmers could employ for Hymenachne infestations. The project included a number of partners including Pioneer Catchment Landcare, Pioneer Catchment Conservation Volunteers & Mackay Whitsunday Natural Resource Management Group now known as Reef Catchments (Mackay Whitsunday Issac) Limited. This report details the findings of a six month, farm scale research project designed to establish an effective eradication strategy for Hymenachne infestations of various sizes.

Project report

Hymenachne Report RCL 0430 Towards a Farm Scale Best Management Practice final report

The Plant

  • Hymenachne amplexicaulis is a perennial grass growing to 2.5 meters in height.
  • The leaf sheath strongly clasps at base with the blades 10 to 45 cm in length by 3-6 cm wide. Hairy at the margins and has light coloured veins.
  • The seed heads are 20 to 40 cm in length and are in a cylindrical, spike like arrangement.


The State of Queensland Department of Agriculture and Fisheries Hymenachne or olive hymenachne, Fact sheet
The Mackay Regional Pest Management Group (2013), Weeds of the Mackay Whitsunday Region, Snap Printing Mackay.

Further information

Hymenachne or olive hymenachne fact sheet
Hymenachne fact sheet

Hymenachne Amplexicaulis.

Hymenachne Amplexicaulis


Chris Barbeler
M: 448 016 158