Tell me NOW!

What is the deal with hyacinth blossoms? I mean how the color drains down and out of them once you've picked them. Of course, this is the fourth day of this bouquet, and I'm really NOT complaining -- it was a gorgeous, fagrant, eye-rolling-back-in-the-head handful of Springtime. But I'm curious. This is the fourth day, and the top three-quarters of the stalk have faded to nearly white, while the lower fourth is much darker purple -- exactly as if the color is slowly draining down the stalk. What's up with that? Nobody online seems to know -- at least, no answers to this question have appeared -- I could spend longer doing some actual research, but I'm a victim of the minute-and-a-half mentality, as far as looking things up. Tell me NOW, or I'm not going to care!