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Invasive plants and animals

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Invasive plants and animals are a significant threat to biodiversity. They include exotic plant and animal species as well as over-abundant native species, which live in both the aquatic environment and on land. The CMA recognises that species may be invasive in some areas but not in others, and that the species targeted for action should reflect the impact they have on biodiversity.

Namoi CMA will focus on species that are considered invasive, and a threat to native vegetation and habitat or which cause other environmental damage eg. erosion. Additionally, activity will be focused on prevention/limitation of spread, rather than eradication or control of extensive weeds.

Targeted species are those that have the greatest negative impact on assets with environmental, economic, social or cultural values and for which there is potential to reverse the negative impact with available resources. (NRC 2005)

Namoi CMA aims to support the work of organisations which have responsibilities for weed and pest animal control eg. local councils, weed advisory committees and Rural Lands Protection Boards (RLPB). The CMA will contribute to coordinated efforts, particularly in strategic planning, and the coordination and implementation of activities that focus on weeds and pests that pose a threat to native plants and animals in the Namoi Catchment.

Namoi CMA is working hard with local weed control authorities and landholders to prevent the spread of high priority invasive species across the catchment.

Foe more information please contact Troy Crittle, Invasive Species Office Namoi CMA on 02 6764 5914 or email

Alligator weed

alligator-weed-180 [alligator weed 180.jpg]Alligator weed (Alternanthera philoxeroides) is a devastating water weed.  It is our highest priority invasive species and is already a problem in 30 countries across the world. Alligator Weed was detected growing along the Namoi River near Gunnedah in April 2012.  Inspections of the river have detected 14 small alligator weed infestations, with the largest being about the size of a small car. Alligator weed has the potential to completely dominate our waterways and to spread downstream to other catchments.  Alligator weed also blocks pumps and affects irrigation enterprises.

Namoi CMA is assisting local weed authorities with funding for boats and survey equipment and is assisting with on-ground inspections to find and destroy alligator weed.  It is not known how alligator weed entered the catchment but our goal is to eradicate it.  You can help by learning to identify alligator weed and reporting suspicious plants to the NSW weeds hotline on 1800 680 244 or your local weeds officer.

Click here for more information about Alligator Weed



Tips to identify alligator weed

Alligator weed is generally distinguished from other plants by its combination of the following three features:

  • Small white papery flowers on short stalks
  • Leaves in opposite pairs
  • Hollow stems.


Tropical Soda Apple

soda-apple-closed [soda apple closed.jpg]Tropical soda apple (Solanum viarum) is an aggressive perennial shrub 1–2 m high.  Tropical soda apple was first identified in Australia in August 2010, however it isbelieved to have been present in this area for a number of years. In late 2010 several infestations were found in the Namoi Catchment.  Tropical soda apple seeds are thought to have been transported with cattle from coastal NSW.   Tropical soda apple has the potential to spread across the catchment if left untreated.  Tropical soda apple is a very high priority invasive species and our objective is to eradicate this weed from the catchment.  

Namoi CMA is working with weed control authorities to search for and eradicate tropical soda apple. NAMOI CMA has also assisted with tropical soda apple education throughout the Catchment.

You can help in eradicating this horrible weed by learning how to identify tropical soda apple and reporting suspicious plants to the NSW weeds hotline on 1800 680 244 or your local weeds officer.

Landholders can assist by monitoring any cattle bought from coastal NSW and quarantining these cattle in yards for 48 hours after transport to the region.

For more information about tropical soda apple click here 


Tips to identify tropical soda apple

  • Tropical soda apple is an upright, much-branching, perennial shrub growing to 2 m in height.
  • It has broad-based, straight, cream-coloured prickles to 12 mm long scattered on most plant parts.
  • Flowers are white, with 5 petals 2–4 mm long. They occur in clusters of 3–6 off a short stem. 
  • Mature fruit are yellow and golf ball-size (20–30 mm in diameter). When immature they are pale green with dark green veins, like immature water melons.



Key Emerging species

Key emerging species are invasive species that are already found in parts of the catchment and have the potential to spread to other parts if their spread is not limited.


Chilean Needle grass

Chilean needle grass (Nassella neesiana) is an exotic invasive grass species native to South America and is closely related to serrated tussock.  Chilean needle grass affects both sown pasture and native grasslands.  The main infestation of Chilean Needle Grass in the Namoi Catchment is centred around Loomberah, south-east of Tamworth.  The main form of spread of Chilean needle grass is by water.   It is relatively unpalatable and reduces farm productivity by displacing more desirable pasture species. It also causes injury to stock and downgrades wool, skins and hides with its long, sharp seeds.

Namoi CMA efforts are focussed on assisting landholders and Tamworth Regional Council to limit the spread of Chilean Needle Grass and reducing the size of the Loomberah infestation.  Outlying infestations of Chilean Needle grass are a high priority for control.

Landholders can reduce the spread of Chilean Needle Grass by controlling infestations and practicing good weed seed hygiene.  Landholders and community members can assist by learning to identify Chilean Needle Grass and reporting infestations outside the Loomberah area and Reedy Creek catchments to their local weed officer.

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For more information about Chilean Needle grass click here


Tips to identifying Chilean Needle Grass

  • Distinctive purple flowers with light green awns
  • The seed can be identified by a distinctive ring called a corona which is a crown like ridge as the base of the seed


Honey Locust

honey-locust-man [honey locust man.jpg]Honey Locust (Gleditsia tricanthus) is a large rapidly growing and very thorny tree.  In the past it has been grown as a fodder and garden ornamental.  Honey locust has formed dense thorny thickets along riparian zones and displaces native plants and animals.  Honey locust thorns can cause injury to people and animals.

Honey locust is present along riparian zones throughout the Namoi and is most abundant in the upper peel catchment around Nundle.  Honey locust spreads by seeds being washed downstream.

Namoi CMA has funded honey locust control operations from Nundle to Tamworth.  As part of this program more than 4000 plants were treated in 2012.  This program continues until 2014.

You can help to prevent the spread of honey locust by controlling plants on your property and by not planting honey locust trees. 




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Namoi Catchment Management Authority, 2013