Pest plants coming into bloom

Taranaki is seeing an early-summer bumper crop of a plant species that’s among the most unwelcome in the region.

An aerial survey last week revealed widespread infestations of giant gunnera, also known as Chilean rhubarb.

The problem is particularly acute in South and Coastal Taranaki.

“We’re most concerned about what we’re seeing,” says Steve Ellis, Environment Services Manager for the Taranaki Regional Council. “Giant gunnera can spread rapidly and smother native vegetation. It’s not wanted here.”

Giant gunnera is among 17 pest plant species targeted in the Council’s Pest Management Plan for Taranaki, which puts legal obligations on the occupiers of land where they are found. In the case of giant gunnera, that means it must be totally destroyed wherever it is on the property.

Other pest plants currently of concern include:

Old man’s beard: This vine covers and smothers native vegetation, and in all but a very few cases it must be totally destroyed on any property where it occurs.

Ginger (yellow and kahili): Both species must also be destroyed. Kahili is currently a particular problem in New Plymouth.

For photos and advice on these species and Taranaki’s other pest plants, go to

Also of concern is yellow bristle grass, which will flower in the coming weeks. This aggressive plant spreads rapidly through pasture, reducing its quality. Cows avoid it, leading to low pasture utilisation.

Farmers who see yellow bristle grass on their property or adjoining road or rail reserves should notify the Council on 0800 736 222. Advice and information is also available on the DairyNZ website: link)

Mr Ellis says the Council works closely with other agencies on yellow bristle grass, promoting best practice for farmers, roading authorities and contractors, and continually reviewing its control – particularly to prevent its spread into the eastern hillcountry.

Because of the characteristics of yellow bristle grass and the way it spreads, it would not be effective to take a blanket regulatory approach such as including it in the Pest Management