“St John’s Wort is our major challenge,” Jamie says.
“It’s a perennial which sits underground and germinates from root and seed,” he says.
“It’s quite hard to kill, and stay on top of, as it slowly takes over.”
He says two years ago they started a concerted campaign to clean up the weed and sprayed 300ha in each year with plans for another 800ha in 2025.
“We try to kill as much as we can when we’re spraying and look to come back every five years.”
The systematic program over the years is designed to reduce the amount of St John’s Wort weeds in the hills and, ultimately, improve carrying capacity with better pastures.
Grazon Extra, from Corteva, has been used effectively in the last two years. It is applied by helicopter at a rate of four litres per hectare, with a double pass helping with coverage and providing excellent control.
A double pass helps with coverage, with excellent control experienced where the chemical has been applied.
The application rate provides solid control of the weeds while maintaining beneficial species such as trees and grasses.
“Grazon Extra has traditionally been the best chemical for the job,” Jamie says.
“We’ve been applying it when the plant is in flower, from late October through to December. It’s a visual thing, so they can see the areas they are spraying, and St John’s Wort can germinate through the summer.”
He says Grazon Extra can also provide good residual control in areas where the chemical reached the ground so will prevent weeds from germinating in the weeks following.
The plan is to remove as many St John’s Wort plants as possible to increase pasture production and reduce health issues.
“It is toxic to livestock so there is certainly a health benefit to getting rid of it,” Jamie explains.
Kuloo Station is dedicated to livestock, with a few flatter paddocks rotated between oats and pasture and the remaining country being quite hilly and steep.
A helicopter is used for herbicide application and a plane for distributing fertiliser.
Jamie says the enterprise backgrounds Angus steers and heifers across the year and is committed to reducing weeds in the pastures.
Grazon Extra is also used to control blackberry on the property through helicopter and via ground rig in the flatter areas.
The herbicide is a combination of three active ingredients to control a wide range of woody weeds and problem broadleaf weeds.