Pori Pori Station in the Bay of Plenty uses a combination of mechanical and chemical control to beat gorse and improve farm production.

“Our aim is to hit gorse as hard as we can the first time with either a bulldozer or herbicide and then use follow-up spraying to control seedling regrowth,” says manager Peter Maguire.

Gorse control is crucial to improving the productivity of the 1550 hectare property, which sits in the foothills of the Kaimai Ranges, west of Tauranga. A diverse operation, Pori Pori runs about 15,000 stock units, including sheep, beef cattle, deer and dairy grazers. The property also has a Kiwifruit orchard.

Peter says the station’s gorse control programme targets a total of 20 to 25 hectares each year.

He says mature gorse (standing up to 2 metres high) on the semi-developed country is usually flattened with a bulldozer and a root rake. The area is then planted with a crop of turnips and, after this has been grazed, pasture is sown. Any gorse regrowth is controlled with herbicide in Spring.

Herbicide is also the first weapon used to control gorse on reverted pastureland. Tordon Brushkiller is applied either aerially or from the ground - depending on the density of the gorse.

“If 60 percent of the targeted area is in gorse, we will use a helicopter. For smaller areas we get in a ground-based contractor.”

A contractor is also used for follow-up applications, one to two years later. Peter prefers to use a professional contractor because he knows the job will be done well and done safely.

He says the choice of herbicide is a crucial factor in effective gorse control and he believes a switch to Tordon Brushkiller two years ago was a sound investment.

“We changed to Tordon for several reasons. Firstly it doesn’t kill the grass and that’s very important because you want ryegrass to survive and suppress weed regrowth.”

The products used prior to switching to Tordon were not grass-safe and this often led to further weed problems. Peter says it was frustrating to see dead gorse replaced by the likes of Woolly Nightshade.

“The beauty of Tordon is that it kills both gorse and Woolly Nightshade without harming the pasture.”

Applied in October or November, Peter says Tordon gives a fast brown-off and an excellent kill. He reckons the benefits make it very cost effective.

“In the past we’ve had to go back year after year to hit regrowth. But Tordon seems to give us better control, and that means we are using less chemical overall to achieve a good result.”

And the backup service is also important. After deciding to change herbicide products, Peter called in Dow AgroSciences representative Hugh Morison.

“Hugh gave us plenty of information on Tordon Brushkiller and he visits regularly to check on progress.”