Pest plant control methods

We use a range of methods in our pest plant operations and you can use some of these on your property. See Weedbusters for advice about which method is the best to control specific pest weeds on your property.

Boneseed can rapidly invade coastal areas and force out native plants. It grows up to 3m tall and each plant can produce up to 50,000 seeds per year. Seedlings are easily pulled out of the ground. Larger plants can be cut at ground level and treated with herbicide.

When planning any plant control control we carefully consider the type of plant, level of infestation, and the location, to decide on the methods for the best outcome.

Ways to control smaller and accessible infestations of pest plants:

• Hand weeding – remove plants from the site to avoid fragments or seed colonising
• Ringbarking or girdling – strip bark around the entire circumference of a branch or trunk of a woody plant
• Mechanical weeding – with weed eaters or rotary slashers
• Controlled grazing – where the weeds are palatable to grazing animals
• Spraying or chemical weeding – spray on the leaves of targeted plants
• Stump treat – if the weed is particularly woody then cut near the base of the trunk and apply herbicide gel or concentrated herbicide
• Check, Clean, Dry your gear – to control the spread of aquatic weeds between waterways

If the infestation is over a large area, where other methods are not effective, these control methods are some of the best options:

• Biological control – a long-term approach to pest control which involves introducing a natural enemy to help control the plant. Landcare Research undertakes the research, strict testing procedures and trialling to ensure that any new organism will only attack the pest plant and no other plant species. More about biological control
• Aerial spraying – used to tackle large scale infestations of gorse or blackberry, for example, where they are unable to be effectively controlled using ground based methods. In most cases the herbicides used are the same as those available at most garden centres. Find out more about safe spraying programmes
• Check, Clean, Dry – Freshwater pest species can move between waterways through human activity. Once established, they can squeeze the life out of our country’s most precious rivers and lakes. Find out more how to protect our waterways by following this simple method - Check, Clean, Dry. 

More information

• Weedbusters – information about pest plants
• Landcare Research - all you need to know about the biological control of weeds and future developments 
• Agpest - a free online tool to assist farmers and agricultural professionals with pest and weed management decision making
• Ministry for Primary Industries - pest plant related matters from the national Biosecurity agency
• NIWA - aquatic weed information