There are fancy products that you can buy to lengthen the life of cut flowers. These is a home recipe to give cut flowers. When I can taking a flower arranging class in college. The teacher told use the cheap recipe for cut flowers.

First you recut the flower stem just before you use them in a bouquet to arrangement them. The fresh cut allows the flower to absorb water. The cut stem tries to heal itself and seals up when exposed to air.

The solution is flat 7-up when the carbonation is gone it is a sugar solution with a little citric acid. This is a substitute for plant sap. I think Sprite will work also. Use regular pop since diet has no sugar so will not work. You can also add a couple drops of bleach. This keeps the bacteria count low. This solution can double the length of time that flower will last. They are products that you can buy to do the same thing. This is an easy way do the same thing for less money.