Auckland is one of the weediest cities in the world, with exotic species outnumbering our native plants.

We have a climate where many weeds thrive. Each year an average of four exotic species naturalise and spread into the wild, with some of these species becoming invasive weeds.

Plants from other countries are naturally controlled there by diseases and things that eat them (animals, insects).

However, many of those natural enemies are not present in New Zealand. We also have a favourable climate, so the weeds thrive here. This is especially true of species from countries on the same latitude as us.

Smothered plants.
Smothered plants.

Weeds can have many impacts on the environment, including:

  • smothering other plants
  • preventing native seedlings from developing
  • excluding all other vegetation
  • out-competing native species
  • preventing native flora from regenerating
  • reducing habitats for native fauna
  • changing ecosystem types and reducing biodiversity.

There are also impacts on human health, Māori values, recreation and primary industry. Some weeds:

  • are poisonous to humans, pets and livestock, such as arum and woolly nightshade.
  • reduce available grazing area.
  • contribute to asthma, such as privet.
  • can destroy archaeological sites, such as on maunga (volcanic cones).
  • in the bush can cause injury through thorns or sharp leaf edges.

Weedspotters network

The Weedspotters network is a community-based volunteer weed alert system to detect new and emerging weeds.

Detecting naturalising plants early makes them easier to control, preventing costly (and often unachievable) eradication in the future.

Anyone can be a Weedspotter, but if you have botanical skills or are outdoors a lot your observations will be particularly valuable.

Auckland Council is interested in newly naturalising and new plant incursions in the region as part of our research for five-yearly Regional Pest Management Strategy (RPMS).  

The aims of the Weedspotter network in Auckland are to detect and control new naturalisations and new locations of total control plant in the RPMS.

To join the network, email us to subscribe to the Weedspotters newsletter.


May 2016 (PDF 3.1MB)
December 2015 (PDF 3.9MB)
July 2015 (PDF 2.1MB)
December 2014 (PDF 3.4MB)
September 2014 (PDF 3.3MB)

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