Japanese Timber Bamboo

I need help with my 6 months old Giant Japanese Timber Bamboo. Google is telling me that curled leaves are from lack of water, but damp soil for the past week seems to have had no effect. I'm afraid its health is deteriorating. There is a lot of new growth on both plants, but the new growth is coming in curly. There is some yellowing happening on one of them also. I'm getting desperate! Any advice would be appreciated.