Posted: 12/05/2015 at 15:46
If you want strong Glyphosate get it at an agricultural store. They may not sell it to you so get a friendly person who they will sell it to, to buy it for you.
And do not buy it ready-diluted at any store if you can help it - it will be very expensive.
Plants may take up to a month to die completely but the poison is inactive as soon as it hits the ground.