Pest Plants

In a number of areas of Wairarapa Moana, pest plants have changed the natural character of the wetlands and have made it difficult for some native plants and animals to thrive. They have also made it difficult for the wetlands to act as sediment and nutrient filters.

  • Aquatic weeds such as hornwort, lagarosiphon, elodea and curled pond weed clog waterways and irrigation equipment and are crowding out native species.
  • Invasive trees and shrubs such as alder, willow, blackberry, gorse and lupin are invading and dominating large wetland areas and the lake edge.
  • Invasive grasses such as tall fescue and mercer grass are out-competing native grasses and are forming an impenetrable barrier for any native species to establish.

What are GWRC and DOC doing?

Work is already underway to try and minimise the impact pest plants are having on the area. Large areas of alder and willow have been controlled and the subsequently cleared areas have been planted with native species. This work is set to continue in the future with the aim of taking the pressure off these areas and allowing revegetation to occur.


Willow & alder treated by aerial spray


What can you do?

The best way to prevent potential weed issues is to stop them from getting into our waterways in the first place. The best way to do this is to Check, Clean and Dry all equipment that comes into contact with the water.

Use the Guide to freshwater pest plants of the Wellington region (PDF, 8927KB) to find out which aquatic plants are pests, how to identify them, which ones to report and what to do about controlling them.

Hornwort Lagarosiphon Spartina

What else can you do?

Always empty aquarium contents onto the compost heap, NOT into or near a waterway or drain. 
Know your enemy.  Learn to identify plants in and around your waterways, or contact the Greater Wellington Regional Council Biosecurity team if you see something new or suspicious. Phone 0800 496734 or email

Did you know?

There are a number of insects and diseases that have been released in New Zealand with the aim of controlling pest plants. Insects have been released on gorse, broom and old man’s beard with varying success. 


Content on this page was last updated: 15/02/2017 9:54am