You may be waiting a long time. Bamboo only flower infrequently and when they do it's a worldwide phenomenon that usually leads to the death of most existing plants of that species. There are long intervals between flowering...like 20-150 years. That is why you can't just go and buy a packet of seed for a specific bamboo species like you would a tomato. At any given time, there are some bamboo in flower, but they may not be anything you are interested in or that would grow in your area. And it's illegal to buy bamboo seed and import it into the U.S., so be careful of where your source is if you buy online.

The original F. nitida is in it's bloom cycle now....mine started the spring of 2008 (I removed it that fall). I expect that it's mostly done by this time. If yours is blooming, it will put out flowers instead of leaves starting in spring. F. murielae is done flowering and plants in trade are new generation. I don't think the other species of Fargesia available are expected to flower anytime soon. In any event Fargesia seem to have a ~100 year bloom cycle for clones.