But just be careful if you do choose to use a chemical method because often 'backyard' gardeners encourage herbicide resistance by not using the right mix of chemical and it only causes the plant to get sick, not die, and this can cause it to become resistant to any chemcial applications in the future, something of a bugbear to us farmers as it only makes it harder for us to control the weeds on a broader scale. Regular glyphosate (RoundUp) will kill it - we only ever use RoundUp around the yard to control weeds as it is the safest for use around children and keep the other stuff for paddock use only. But unless you know someone who knows someone who can buy chemcials other than RoundUp you wont be able to buy it anyway.