Do you use herbicide at every planting site? 

No. Some of our landowners and partners choose herbicide-free options. We always stay clear of waterways if spraying. 

Why do you use herbicide? 

Weeds and rank grass can choke native plants. When we replant with natives, we want them to reach a height where they can survive independently. Herbicide allows us to kill weeds reliably and quickly. This means we can cover more ground, work efficiently and achieve the long term benefits.  

How do other (manual) weed control methods compare?  

They take much more time and need to be repeated more often. That’s because many weeds can regrow from fragments, bulbs or roots in the ground. Pulling and grubbing turns the soil over and opens up space for weed growth. Manual methods are often appropriate in private gardens, where the gardener dedicates time for ongoing weed control. However, as a professional team with limited resources, we want to do as much good as possible – and herbicide helps us with that. 

Which herbicides do you use? 

Our main herbicide is glyphosate - a popular, tried and tested weed killer. We dilute it with water to use as little as necessary. To make sure it sticks to the weeds, instead of running off, we use an oily additive. We also add a little penetrant to help the spray get into the leaves, where it will spread throughout the plant and roots. We add coloured dye so that everyone in the team can see what has been sprayed so we don’t double up or miss anything. In some cases, if necessary, we may use a different herbicide – for example, Vigilant for woody weeds. 

Does herbicide stay in the soil? 

Glyphosate binds relatively well with soil, which is good because that makes it harder for the herbicide to wash in waterways or groundwater. It is broken down in the soil (biodegradable), meaning residues in the soil are not the active ingredient. Rain and soil make the herbicide less active over time. The active ingredient is reduced by half in two weeks.

Are herbicides safe for people and the environment? 

In New Zealand, the Environmental Protection Agency (EPA) has approved the herbicides we use as safe if used according to manufacturers’ labels and instructions.

Our choice of herbicides and careful application onto weeds ensures any risks are minimised.

During and shortly after spraying, it is recommended that stock, pets, and children are kept away from the area. However, once the plants are dry, it is safe to walk through. Fresh spray can cause irritation on skin and eyes, which is why we use protective gear. 

Overseas, mass-scale use of glyphosate on food crops caused public concern and anti-herbicide reaction. However, it was recently concluded that, if used correctly, the chemical is not dangerous for humans or bees (wrong additives and improper use are). We avoid spraying over native plants or waterways and have measures to contain a spill if it happens.  

What precautions do you take when using herbicides? 

Our team is trained in correct use of herbicides. When we spray, we use the right gear and clothes to protect the team. We spot spray where it’s needed, and spray drift or run-off are prevented. We spray in good weather only. We keep away from waterways and water bodies. We follow all manufacturer instructions and have a containment kit in case of a spill, and always carry a first aid kit.