Japanese knot weed. I have it at the back of my garden and when I moved in I was told it would take up to two years to be treated and gone, but today I have been told they will only treat it once a year and its marked down as 2028 for the last lot of treatment if there's still any signs of it can anyone tell me if this is right or if the council have to do it more often to get rid of it quicker?Japanese knot weed. I have it at the back of my garden and when I moved in I was told it would take up to two years to be treated and gone, but today I have been told they will only treat it once a year and its marked down as 2028 for the last lot of treatment if there's still any signs of it can anyone tell me if this is right or if the council have to do it more often to get rid of it quicker? It is fenced off but I've lost 3/4 of my garden and by the sounds of it not just for two years.