I think this section covers his problem and is pretty much what I was saying.
And If the Above Methods Just Don't "Cut It"....
The American Bamboo Society recommends a different approach to getting rid of bamboo: cutting. Since their specialty is bamboo, I would lend the most credence to their advice, which, in sum, runs as follows:
- Cut the bamboo shoots down
- Apply water to the area
- Cut down the new crop of bamboo resulting from #2
- Repeat the process until shoots stop coming up.
The idea behind doing all of this is to deplete the reserves of energy in the plants' rhizomes, after which they will not be capable of sending up new shoots.
Those reserves are no longer being replaced, because you are removing the plants' mechanism to do so -- photosynthesis -- by depriving them of vegetation. They can only hold out so long without being replenished (although it may seem an eternity if you are itching to be rid of the plants so that you can start a garden in that spot).
As a concluding observation about using this method, the American Bamboo Society writes that, once you are done, "The rhizomes will be left behind, but will rot away." The reason that these old rhizomes will rot away is that they have been depleted of their energy reserves. By contrast, when you use the digging method (discussed above), the rhizomes you leave behind are still fresh -- and that is why they generate new shoots (rather than just rotting away).