Amy from Eugene, Or writes
Normally if you are trying to kill any plant you want to apply an herbicide when the plant is actively growing and soil temperatures are above 65 degrees consistently. Otherwise waiting until the plant is dormant for the season and doing manual cutting down and elimination is always an option. If you choose to use an herbicide you would want to go with a brush killer like Fertilome Brush Killer and Stump Killer and follow directions for diluting and application per the product label.
Answer last updated on: 01/31/2016