As part of the No More Glyphosate NZ Council Herbicide Transparency Project, we asked councils across New Zealand about herbicide use in public spaces, the products being used, the policies governing their use, and whether those practices have been formally reviewed.
Selwyn District Council provided a detailed written response describing herbicide use across roads, footpaths, cycleways, drainage infrastructure, parks, reserves and sports surfaces. The council identified a range of herbicide products and active ingredients, outlined its contractor-based vegetation management practices, and explained the operational standards and public notification procedures governing spraying.
Of particular interest is Environment Canterbury resource consent CRC201738, which the council states authorises specified herbicide and surfactant applications to roads and water races, including circumstances where agrichemicals may enter land or water. While the response acknowledged the use of physical and mechanical weed-control methods, it provided limited detail about their extent and did not identify a recent comprehensive review of the council’s herbicide-use practices.
Quick Summary
- Glyphosate is among the herbicides authorised for use under the council’s resource consent, and Roundup is listed among products used by its Parks and Reserves division.
- Other authorised herbicides include metsulfuron, diquat, haloxyfop, terbuthylazine and triclopyr.
- Herbicides are used around roads, drainage infrastructure, footpaths, cycleways, parks and sports surfaces.
- Playgrounds are not sprayed directly, according to the council, although herbicides may be applied to surrounding garden beds.
- Contractors undertake vegetation control through regular inspections, with identified vegetation generally required to be treated within five days, subject to weather conditions.
- Public notification includes warning signs, turf re-entry notices and some social media announcements.
- Physical and mechanical weed-control methods are also used, although the council did not explain their relative use compared with chemical treatments.
- The council confirmed that proposed new herbicide products are reviewed internally for suitability and community safety, but did not identify a recent comprehensive review of its overall herbicide-use programme.
What We Learned
Herbicide Use Extends Beyond Parks and Reserves
Selwyn District Council’s herbicide programme covers considerably more than the maintenance of parks and recreational areas.
Under Contracts 1420 and 1421, contractors are responsible for vegetation control across sealed and unsealed roads and associated infrastructure.
The council identified applications around:
- Bridges, culvert headwalls and abutments
- Road signs, sight rails and edge marker posts
- Kerbs, channels and soakholes
- Water races and land drainage assets
- Paved and gravel medians
- Footpaths and cycleways
- Driveways forming part of the road or footpath network
Vegetation is controlled where it obstructs infrastructure, interferes with drainage or affects the appearance of maintained public areas.
On footpaths and cycleways, herbicides may be applied when vegetation encroaches on usable surfaces.
Sports surfaces may also receive herbicide treatments during renovation periods where inspections or testing identify unwanted vegetation affecting turf performance.
What About Playgrounds?
The council states that herbicides are not applied within playground areas.
However, it also confirms that herbicides may be used in surrounding garden beds as part of routine maintenance.
This distinction is important for parents and caregivers. A playground itself may not be sprayed, while nearby planted areas within the same reserve may still receive chemical treatments.
The response does not specify minimum separation distances between treated garden beds and playground equipment or play surfaces.
Herbicide Products Identified
Selwyn District Council provided information about both herbicides authorised under a resource consent and commercial products used by its Parks and Reserves division.
Herbicides Authorised Under Resource Consent
The council operates under Environment Canterbury resource consent CRC201738, which permits applications of herbicides and surfactants to roads and water races, including circumstances where agrichemicals may enter land or water.
The herbicides identified as approved under the consent are:
| Herbicide active ingredient or group | General herbicide classification |
|---|---|
| Glyphosate | Broad-spectrum, non-selective herbicide |
| Metsulfuron | Selective systemic herbicide |
| Diquat | Non-selective contact herbicide |
| Haloxyfop | Selective grass herbicide |
| Terbuthylazine | Residual herbicide |
| Triclopyr | Selective broadleaf and woody-weed herbicide |
These are substances authorised under the consent, not necessarily evidence that every substance is currently being applied.
The council did not provide quantities used or a breakdown of applications by active ingredient.
Products Used by Parks and Reserves
The council separately identified the following commercial products:
- Agpro Lawn Clean
- Fiestar
- Grazon
- Sukka (wetting agent)
- Roundup
- Terb 500
- Tordon / XT
- Victory Gold / Triumph Gold Gel
- Vigilant Gel
- Ignite
- Agritrade Surrender
This list includes herbicide products and a wetting agent.
The response does not provide formulation details, concentrations, annual usage quantities or the locations where each individual product is applied.
As commercial formulations can differ, the product names alone should not be treated as a complete record of the active ingredients used.
How Frequently Are Areas Sprayed?
Selwyn District Council describes vegetation control as an inspection-based maintenance activity.
Under its road and infrastructure maintenance contracts, vegetation identified during regular inspections must be sprayed within five days, unless weather conditions are unsuitable.
The council also requires vegetation growth to remain within specified maintenance limits between inspection cycles.
While this establishes how quickly contractors must respond to identified vegetation, it does not, by itself, establish how many times a particular road, footpath or other location is sprayed annually.
Policies, Standards and Safety Requirements
The council states that its herbicide practices follow NZS 8409:2021, New Zealand’s standard for the management of agrichemicals.
It also refers to compliance with the Hazardous Substances and New Organisms Act and Environmental Protection Authority requirements.
Contractors must have appropriately trained and certified personnel.
For road and infrastructure maintenance contracts, contractors are required to nominate a certified applicator during the tender process and notify the council of personnel changes.
These requirements establish an operational framework for agrichemical handling and application.
However, compliance with an application standard is not the same as undertaking an independent assessment of whether chemical weed control remains necessary or whether alternative approaches could reduce herbicide use.
Public Notification and Awareness
Selwyn District Council reports several methods of notifying the public about herbicide applications.
Warning Signs
Contractors are required to display signs warning that spraying is in progress.
The council states that these signs remain in place for at least 24 hours.
For turf areas, additional re-entry signage identifies:
- The area being treated
- The chemicals used
- When the public may safely re-enter
- Contact information
Depending on the treatment, re-entry instructions may specify waiting until the treated surface is dry or for a period such as 24 hours.
Social Media and Scheduled Spraying
The council also uses social media to inform residents about planned spraying.
However, scheduled treatments may be postponed because of weather conditions, including wind that could increase the risk of spray drift.
The council publishes information about its waterway spraying programme, including areas, chemicals and proposed application dates.
Council information:
Selwyn District Council — Waterway Spray Programme
What About Residents Who Wish to Avoid Spraying?
The response does not identify a no-spray register or explain whether residents can request alternative vegetation-control methods near their properties.
Nor does it describe specific advance-notification arrangements for chemically sensitive residents.
This does not necessarily mean such arrangements are unavailable, but they were not established by the information supplied.
Non-Chemical Alternatives
The council confirms that its Reserves Operations team uses physical and mechanical methods alongside herbicides.
However, it provides no further detail about the methods used, the locations where they are preferred, or their effectiveness.
It also does not identify any specific trials intended to reduce reliance on chemical weed control.
The existence of alternative methods is encouraging, but the response provides insufficient information to assess how extensively they are used.
For example, it remains unclear whether mechanical control is the preferred approach in particular public spaces or whether herbicides continue to be the routine default.
November 2026 — Plant Growth Regulator Trial at Brookside Park
In a separate public announcement, Selwyn District Council advised that it would trial a chemical plant growth regulator at Brookside Park on 4 November 2026, with the aim of slowing grass growth and reducing mowing frequency.
Responding to a public enquiry on Facebook, the council identified the product as Primo Maxx, a plant growth regulator containing trinexapac-ethyl.
Unlike conventional herbicides, Primo Maxx is designed to suppress grass growth rather than kill vegetation. The council stated that treated areas should be avoided by people and animals until the spray has completely dried.
The trial was announced several months after the council’s LGOIMA response and is therefore not part of the original disclosure. Nevertheless, it provides a further example of the council’s use of chemical treatments in public recreational spaces, including products intended to reduce mowing frequency.
Source: Selwyn District Council — Facebook announcement
Review History and Safety Assessments
One of NMGNZ’s questions concerned the scientific and regulatory information councils rely on when assessing herbicide safety, and whether recent internal or independent reviews had been undertaken.
Selwyn District Council stated that proposed new products used by contractors are reviewed internally for suitability and community safety.
It also referred to monthly chemical-use reporting by contractors.
However, the council did not identify:
- A comprehensive review of its herbicide-use programme
- The date of its most recent formal policy review
- An independent assessment of the safety of its current practices
- The scientific evidence considered when determining whether existing herbicides remain appropriate
- Any formal comparison of chemical and non-chemical approaches
Although the council confirmed that proposed new products undergo internal review, it did not provide details of any recent comprehensive assessment of its existing herbicide-use programme. This does not establish that no such assessment has taken place, only that none was identified in the information supplied.
There is also an important distinction between assessing a proposed new product and periodically reviewing an established herbicide programme.
A product may have been used for many years without its continued use necessarily having been reconsidered in light of newer scientific findings, changing community expectations or available alternatives.
Documents and Information Provided
The council’s response identified the following supporting information:
Resource consent: Environment Canterbury CRC201738, covering specified herbicide and surfactant applications associated with roads and water races.
Operational contracts: Contracts 1420 and 1421, governing vegetation control across road and infrastructure assets.
Waterway spraying information: Publicly available programme details, including the 2025–2026 spraying schedule.
Application standards: NZS 8409:2021 and applicable hazardous-substances requirements.
The response referred to regular inspection cycles, monthly contractor chemical-use reports and internal product reviews, but did not include those records in the material available for this report.
NMGNZ Observations
Selwyn District Council’s response provides useful insight into how herbicide use is incorporated into routine infrastructure and public-space maintenance.
It identifies a relatively broad range of authorised herbicides and commercial products, along with some of the operational requirements imposed on contractors.
The council also distinguishes between playgrounds, where it says herbicides are not applied, and surrounding garden beds, where spraying may occur.
However, several issues warrant closer attention.
First, the extent of routine spraying remains difficult to quantify. The council describes inspection-driven vegetation control but does not establish how frequently individual locations are treated or how much herbicide is applied annually.
Second, the resource consent raises questions about applications around water infrastructure. The council states that consent CRC201738 permits specified herbicide and surfactant applications to roads and water races, including circumstances where agrichemicals may enter land or water. However, the response does not provide the consent conditions or establish how frequently applications occur in these circumstances. Examining the consent conditions and associated environmental safeguards would provide important additional context.
Third, the response provides limited information about the council’s review process. Internal assessment of proposed new products is not equivalent to a comprehensive review of existing herbicide practices.
Finally, the council acknowledges the use of non-chemical alternatives but does not explain their role within the overall programme. Without that information, it is difficult to assess whether reducing chemical use is an operational priority.
These are questions about transparency, evidence and decision-making rather than proof of unsafe practices.
Why This Matters
Herbicide applications in public spaces affect areas that residents encounter in everyday life — roadsides, walking and cycling routes, recreational reserves, sports grounds and drainage corridors.
For many people, exposure may not involve a single identifiable spraying event. It may involve repeated use of public spaces where vegetation is routinely managed with herbicides.
That makes information about application frequency, products used, public notification and the reasoning behind weed-control decisions particularly important.
Selwyn District Council has disclosed a substantial amount of information about its operational arrangements. But important questions remain about how much herbicide is used, how often particular locations are treated, and whether established practices are periodically reassessed.
Public confidence requires more than assurances that spraying follows established standards. It also requires sufficient information to understand what is being applied, where, how often and why.
That is the purpose of the No More Glyphosate NZ Council Herbicide Transparency Project: to make information about council herbicide practices more accessible and to encourage informed public discussion about their continued use.
About This Information
| Item | Details |
|---|---|
| LGOIMA Reference | 2133 |
| Request Submitted | 4 May 2026 |
| Council Response | 25 May 2026 |
| Information Source | Official council response under the Local Government Official Information and Meetings Act 1987 |
This report documents information provided by Selwyn District Council in May 2026. Herbicide products, contracts, application practices and council policies may have changed since that date.
