I am having the same weird problem. Two 8-yr-old clumps of golden bamboo (Phyllostachys spectabilis) in my Seattle yard are also dropping hundreds of their new, green spikes of leaves--unopened--and the tops of the newest canes are stunted, soft, and breaking off. Canes less than full height are turning flaccid and dying back to the ground. Old leaves are turning yellow and dropping while others are still green and healthy. There are no rolled or wrinkled leaves indicating that the soil is too dry. An adjacent clump of black bamboo nearby looks normal. I gave everything a good soaking yesterday even though the soil wasn't particularly dry within the root barriers. Wait and see are next. I have no idea what stressed the golden bamboo so badly, but it was something very recent, judging by the full formation of the first spring canes and the dieback of the later growth. Maybe a family of voles moved in last month after my neighbor finally mowed his knee-high grass. Maybe it's the weird weather. If anyone else is having similar problems, I would like to hear about it.

I agree with gardener1...you will not help the health or the permanent appearance of the plant by pruning now. You say "half" is yellow. Does that mean one of two culms has turned yellow or what? If so, it could be the natural cycle and you have a dying culm (they last about 7 years on average), which could be completely pruned out after several months if you get no re-growth. Bamboo generally do best in the ground, not indoors, even if you do take it outside periodically. If the air is dry inside this time of year, that could explain why it is not doing well. Do you mist it? And why don't you plant it? Is it not hardy enough? Also, what species is it?

Place it in diffused sunlight. like room with a window through which sufficient amount of light enters. but remember "not to place it directly in sunlight". Little bit of yellowing is okay as new leaves are coming...

Hi. You don't have to worry about the black spots on you plant. If the leaves are turning yellow just cut them off. A reason the leaves are turning yellow may be because your plant is getting to much sunlight, or the filtered water you are feeding it is not room temp. Also try spraying your bamboo with filtered room temp water. I don't think you have to transfer it to another big container for the roots to grow. Good luck!