Water Celery and other Pests

January 26th, 2024

Waitītiko Meola has a new weed infestation: water celery or Helosciadium nodiflorum

Here are some facts on water celery, and some actions we can take. The picture below is in Watea Reserve – the long tubular stem on the left, and there are some leaves. Better photos are in the articles below.

New Zealand Plant Conservation Network is an excellent reference point for natives and weeds. See what it says at  https://www.nzpcn.org.nz/flora/species/helosciadium-nodiflorum/

It appears it sprouts from both seeds and shoots in the soil.  In our catchment is already found at:

  • the wetland at Watea Reserve. 
  • the wetland on Roy Clements treeway (RCT) 
  • Meola Creek behind Waiorea recycling centre 
  • on a meander near Moa Reserve in Point Chevalier

Weedbusters NZ https://www.weedbusters.org.nz is normally an excellent source for pest plant eradication, but it doesn’t list it.  While it has been a problem in Wellington and Nelson, it is new in Auckland it seems. And it likes wetlands.

Landcare are planning to find some biological controls, which gives some hope in the long term… (Thanks to Christina Robertson for reference)  https://www.landcareresearch.co.nz/publications/weed-biocontrol/weed-biocontrol-articles/a-new-aquatic-weed-on-the-radar/

If we look on pest database for Auckland, https://www.tiakitamakimakaurau.nz/protect-and-restore-our-environment/pests-in-auckland/pest-search/ it is also not listed there. This means Auckland Council doesn’t yet officially recognise it, which can mean weed removal is more difficult. However we have spoken with Auckland Council who expect to undertake some work soon.

Fortunately the Auckland Council (AC)10 year plan is also being finalised and we the public can submit that water celery and other emergent pests should be added. Using words like “environmental weeds”, “emergent pest plants” etc should help retain the Biodiversity targeted rate which funds pest plant removal amongst many other priorities.

The dates for input to AC 10 year plan are 28 February to 28 March 2024. We urge all STEPS members to put in a personal submission at https://akhaveyoursay.aucklandcouncil.govt.nz/hub-page/long-term-plan-2024-2034   which already shows the Mayoral Proposal so we can start reading now! 

Other key points for submitters relate to the retention of the Water Quality Targeted Rate, which is funding the pipes which connect local waste water pipes to the new Central Interceptor. It’s a critical piece of work if the hundred thousand residents in Meola catchment are to gain some reductions in waste water pollution. In our submission we will mention “stream restoration” and “water quality” as key concerns.

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