Central Otago District Council Herbicide Use and Public Space Spraying

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.

Central Otago District Council provided a detailed written response describing herbicide use separately for its Parks and Road Reserve operations. The council identified the products used, where they are typically applied, the general frequency of application, the operational guidance relied upon, and the alternative weed management approaches currently used within parks.

The response also outlined how spraying is managed around sensitive public areas, described the council’s public notification practices, confirmed the existence of a Road Reserve no-spray register, and advised that no formal internal or independent review of herbicide use has been undertaken in recent years.

Quick Summary

What We Learned

Central Otago District Council advised that herbicide use differs between its Parks and Road Reserve operations.

Within parks and playgrounds, herbicides are selected according to the target plant species using recommendations provided by chemical suppliers. The council stated that most products are glyphosate-based, with additional products used to improve spray performance or for targeted control of specific noxious weeds such as broom and gorse. Parks and playground areas are generally treated two to three times per year depending on seasonal growth.

Road Reserve vegetation management uses a broader range of herbicides and adjuvants. Annual spraying programmes are scheduled according to roadside, urban, and pest plant management requirements, with additional targeted treatments undertaken where necessary.

The council also advised that parks staff are actively pursuing several non-chemical weed management approaches to reduce overall herbicide use while maintaining service standards, whereas Roading has not considered non-chemical alternatives at this stage.

Products Identified

Note: Active ingredients have been identified from publicly available product information where they were not explicitly stated in the council’s response.

Application Locations and Frequency

Parks

The council advised that herbicides are used within parks and playgrounds. Most applications occur two to three times each year, depending on seasonal growth.

Products are selected according to the target plant species, with glyphosate-based herbicides forming the majority of treatments, and other herbicides are used for targeted noxious weed control, including broom and gorse.

Road Reserve

Road Reserve herbicides are used for roadside and footpath vegetation control, urban vegetation management, and pest plant control.

The council described its annual programme as follows:

• Roadside: August each year (approximately 2–3 weeks), with sites near vineyards and orchards completed before 1 September. One spray per season with a second targeted round if required.
• Pest Plants: Treated throughout the year, with emphasis from April through winter before spring growth.
• Urban Areas: Spraying begins after roadside operations from September onwards, with a second round during March–April.

Policies and Guidance

The council advised that its operational guidance is based primarily on information provided by chemical suppliers.

For parks, product selection follows industry-standard recommendations from suppliers, with staff maintaining awareness of sensitive public spaces including playgrounds and schools when planning spraying activities.

For Road Reserve operations, the council stated that herbicide selection is based primarily on effectiveness for the vegetation being controlled.

The council also advised that herbicides used in both parks and road reserves are EPA-approved products.

Public Notification and Chemically Sensitive Residents

The council advised that neither Parks nor Road Reserve operations have a formal public notification system before spraying.

For parks, temporary “Spraying in Operation” signs are placed at key locations around active work sites to provide public notification while spraying is underway.

For Road Reserve operations, the council maintains a no-spray register for landowners who do not wish chemical vegetation control to occur in front of their properties.

Review History

The council advised that no internal or independent review of herbicide use or herbicide safety has been undertaken in recent years.

For both Parks and Road Reserve operations, the council stated that its current approach has not been formally reviewed and that it relies on advice from chemical suppliers regarding herbicide methodology and application practices.

Observations

Central Otago District Council provided one of the more operationally detailed responses received as part of the Council Transparency Project, separating its answers between Parks and Road Reserve activities.

The response identifies a comparatively broad range of herbicides, adjuvants and related products used across different operational areas, together with seasonal application programmes for roadside vegetation management.

The council also distinguishes between departments when discussing alternative weed management. Parks staff described several non-chemical measures currently being used to reduce herbicide reliance, while the Roading section advised that it has not considered any non-chemical methods at this point in time.

Although the council outlined the operational guidance it follows, no standalone herbicide policy, standard operating procedure, contractor specification, or review documentation was supplied with the response.

Why This Matters

Councils manage a wide range of public spaces on behalf of their communities. Understanding what products are being used, where they are applied, and how decisions are made helps contribute to greater transparency around weed management in public areas.

The Council Transparency Project aims to build a nationwide public record of herbicide management practices across New Zealand local authorities so residents can better understand what is happening in their own communities.

Information Request Details

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