Why is my bamboo dying?

i have 3 stalks of bamboo and they live in a vase of water with rocks at the bottom. i've had them for several years and this winter is the first time that the leaves have started to turn yellow, then brown, and then shrivel up. the yellow is progressively making its way down the entire stalk. i know next to nothing about plants, so do i cut the dead part of the leaves off, do i put something in the water, do i plant them in soil?

Why is my bamboo dying?
This "bamboo" is not real bamboo but rather a Dracena plant. The symptoms you describe tell me it is a root problem. Did the leaves start browning around the tips first? Did you change anything? Like the water, amount of water, the location, did you spray it with anything? Look on the back side of the leaves to determine if you have insects. Spider mites could cause this. You can also take a piece of white paper and tap the leaves to see what fall off. You could technically plant these in soil but due to the time they have spent in water I don't think they will survive.
Reply:As "Perplexed"mentioned the "Lucky Bamboo" you have is actually a species of Dracaena. Since you have grown it hydroponically for several years, the root cells are accustomed to water and would die if planted into soil.

Good for you for keeping the Dracaena alive so long in water! Unfortunately, they do not live forever this way...and your plant is slowly dying.
Reply:It is dying because seven years is its lifespan.