[quote]I've just looked in search and seen something on Japannese knotweed, but I don't think it's what I have. It's a tall plant with very stubborn roots, called japanese something. Neigbours have it as a h...[/quote] A bit late posting to this but Jap Knotweed has red vertical stips on the stems. Mine is definetly french at least 4 generations. I am winning the war. Most effective solution I have found is to cut off the growth approx 20 - 30 cms above ground and insert a spike down the inside of the hollow stem to be low ground level breaking the internal knuckles of the stem. (like bamboo cane) remove spike then pour neat round up down the stem. It gets the stuff down to the roots more quickly rather than spraying the leaves and waiting for it to be absorbed into the plant. Obviously spay all young / new shoots when approx 50 cms high. Burn all the stuff you cut down straight away. Colin