I want to remove a large patch of bamboo in a shady part of my back yard. I cut down all bamboo to the ground. Now I need to deal with the roots. I would like to kill the roots, but using a "green" method where I won't use glyphosate or other chemicals that are harmful to the planet. I've read on the internet that some peole recommend using a high nitrogen fertilizer & cover with plastic sheeting to basically cook the roots thereby killing the bamboo. Another resource told me that constant cutting back of the bamboo over a couple of years would also kill the roots due to lack of photosynthesis. Do you have any suggestions on how to kill the bamboo without using harmful chemicals?