Working together to protect New Zealand

Weed Information

Controlling Pest Herbs & Ground Covers

Dumping weedsPest ground covers and herbaceous plants can smother native plants and prevent native seeds from germinating and growing.

Pest plants like wild ginger, montbretia, and tradescantia (wandering jew) are notoriously hard to get rid of and need consistent effort. If you are unlucky enough to have them, below are some options.

Dig or pull treatment

This is appropriate for small infestations.

Make sure you remove all the weed growth from the ground including leaves and underground stems, corms and roots since many pest herbs can grow from small stem fragments (e.g., selaginella, tradescantia).

A variation on this treatment for tradescantia is to roll growth like a carpet to avoid breaking into too many pieces.

Be very careful you don't drop pieces when you move waste material from the site. Put it in a plastic bag and dispose of it carefully.

Keep revisiting the site regularly to pull out any new growth.

Spray

Large infestations may need spraying.

6 tips for spraying

  1. Check the best time of year to apply the spray. Plants usually absorb the most lethal dose of chemical during growth spurts prior to flowering or fruiting.
  2. Check you have the correct herbicide for the weed you want to kill.
  3. Follow the manufacturer's instructions regarding mixing and application. Do not dip used containers into a water supply, and if you're spraying over or near water, ensure you're using the recommended spray.
  4. Add a sticking agent (surfactant) to improve the effectiveness of the spray. You could also consider using marker dye to see where you've been, or a foaming agent to minimise spray drift.
  5. Choose fine, calm weather. A very light breeze can help you control the direction of spray drift.
  6. Cover new plantings when spraying nearby.