Im pretty sure it is due to frost damage. I think the bamboo would be larger by now, but all the large culms die in the freezing weather and every spring it starts out with these small shoots. It usually starts sending out new large shoots mid summer and continues growing progressively larger shoots until fall. I wonder If I protected it in the winter if it would start out in spring sending up large shoots? I tried 2 years ago and built a small wire and plastic structure around the bamboo, but we had several hard freezes that year and all the culms died anyway.
