Need to poison Blackberries, Grazon Extra Herbicide is primarily used for brush weed control plus difficult to control broadleaf weeds in fallow situations in northern Australia. In Southern Australia it is the standard for volunteer Lucerne removal prior to cereal cropping. Treatment tips • Avoid using foliar applied herbicides on blackberries that are moisture-stressed or grazed heavily at the time of application. • Spray regrowth when runners are at least 1m long after slashing, burning or grazing to allow sufficient leaf area to absorb enough herbicide to control the root system. • Ensure all canes and leaves are sprayed, including those growing from suckers away from the main bush. Spray in the period from petal fall to leaf fall. For best results Spray to thoroughly wet all foliage and canes. Ensure peripheral runners are sprayed. Use the higher rate on on difficult-to-kill blackberry.