We use a range of methods to control pest plants in our region. Some of these can be used on your own property, providing that safety precautions are followed carefully.

When planning any plant control, we carefully consider:

  • The type of plant
  • Where the control needs to take place
  • The level of infestation

These considerations help us to decide on the methods for the best outcome.

There are some pest plants that we may be able to control for you, while some are best managed by landowners on their own properties.

Small jobs

Ways to control smaller and accessible infestations of pest plants:

  • Hand weeding– remove plants from the site to avoid fragments or seed colonising.
  • Ringbarking – 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 and/or stems of targeted plants.
  • Stump treat–woody plants can be cut near the base of the trunk, and herbicide gel or concentrated herbicide can be applied.
  • Drill and Fill – drill angled holes into the stem of woody weeds (down to the sapwood), then fill the holes with herbicide.

Large jobs

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

  • 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 aerial spraying.
  • 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 about Check, clean, dry.
  • Biological control– a long-term approach to widespread pest control which involves introducing a natural enemy to help control the plant. Manaaki Whenua 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.

Greater Wellington contributes towards the National Biocontrol Collective which includes the majority of regional councils, DOC and several district councils. Find out more about Biological control.

Removing plants

  • Research first – find out about the weeds you’re dealing with first and if necessary, ask for expert help.
  • Start small – avoid creating large cleared areas which can allow new and different weeds to establish.
  • Work in stages – tackle outlying weed patches first to slow the rate of weed spread before starting on the worst areas.
  • Keep safe – Always follow the safety precautions of any herbicide carefully.
  • Good timing  destroy weeds before they fruit or seed to prevent a new generation of weeds.
  • Don’t spread them – when shifting dead weeds take care not to spread any seeds or fragments around that could grow again.
  • Smart disposal – decide on the best disposal method to use before you start, particularly if working in a large area

Keeping them away

Taking out weeds will often open up the area for other weeds to grow. Here’s how to avoid replacing one problem with another:

  • Replace bad with good – plant natives or non-weedy plants as you go. Download this free Plant me instead booklet
  • Help native seedlings– by providing shelter and controlling pest animals
  • Mulch– this discourages weeds and helps good plants grow
  • Regular attention– ongoing control of weeds keeps maintenance at a manageable level. Use selective herbicides so non-target plants survive and follow the directions closely.
Updated November 16, 2021 at 9:19 AM

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