This pest plant is a prickly potential spreader that we hope to keep out of Tasman.
Gunnera tinctoria – otherwise known as Chilean Rhubarb – looks like a large rhubarb plant with spikes on the leaves and has historically been planted around pond edges as an ornamental plant.
Due to its pesty tendencies in waterways, Gunnera is a National Pest Plant Accord listed species, meaning it is banned from sale, distribution and propagation in Aotearoa.
It is listed as a Sustained Control Pest in our Tasman-Nelson Regional Pest Management Plan. This means it is a requirement of occupiers in Nelson Tasman to control Gunnera and prevent its spread to other areas.
Gunnera is from South America. It can grow over two metres tall and produces long seeding cones containing up to 80,000 tiny seeds. These are spread by washing down open drains and river systems.
In heavily infested Gunnera areas, it has been proven that small birds can eat the seeds and spread them well away from water systems. While it likes damp feet, Gunnera can also grow away from water.
We recommend spraying foliage with Triclopyr 600 EC or cutting off at ground level and pasting the stump with Vigilant (picloram) or double-strength glyphosate gel.