I am told that bamboo culms don't put on any more height after the first season. That's is also my experience up here, but we are only barely able to grow the most cold hardy species. If that is the case for you, too, then a mow-down approach might induce an explosion of growth, culminating in taller growth. (I love puns!
) On the other hand, it might set them back. While my mow-downs are out of necessity....(when winter die back is too ugly), you might want to do some experimentation rather than going going whole hog.