could you approach your neighbour and ask him to reduce it on his side and once this has been achieved dig a channel on your side and sink down some steel sheeting aprox two to three feet, it may be killed off wth glyphosphate by cutting down the stems to six inches on your side and trickle down the stems with the weedkiller, have not tried this on bamboo but have used this method succesfully on eradicating japanese knotweed, but speak with your neighbour if you can, hope this helps, Julien

bamboo is such a tuff plant .as julien sais chat with the nieghber.i had to kill some that was about to break my pond down.i cut it down after trying a weed killer,i poured weed killer down the stems . i took all the light away from it for 3 years.i poured a 56 lb bag of salt on it and every opertunity i poured a kettle or 2 of boiling water on it.after 3 years i couldnt get the roots out still but it was about dead.i finished it of bye building a huge concrete sculpture ofer the remaining shoots.this plant was 20" round and i didnt have the parent plant next door.i think your going to have some real trouble hear. you can bye a membrane to go right down the length of your border 60cm wide and as long as you want it from bamboo suppliers.i used it myself.the trouble is once you dig up the bamboo your side which i can tell you wont be easy any gaps in what you use as a barrier will be found bye the bamboo and the prosess will start again .this barrier is nylon,flexible and you can get it as long as you want.bamboo is emencly strong but only sends the rizomes out in the top 10"- a foot of the soil generaly. i think this problem is going to crop up again and again.good luck .you just mite have to seek professional help on this weather it be council or maybe a soliciter or hopefully get your neighber to dig the whole of his plant out.i just dont see why you should do all the hard work for what is your neighbers lack of judgement or understanding.maybe your nieghber is friendly and you can work something out.ill keep my fingers crossed.this mite sound harsh but its true .