When you have cut flowers and even if you quickly put them into water, They will die soon
afterwards as they've been taken away from the flowers food source in the earth and the stems. The leaves will begin to turn yellow then brown as they also have lost their
food sources too. Also from the natural sunlight too.
But just a tip from something that I do, when I have cut flowers then a way to make them
live longer, I add half a teaspoon of sugar into the water.