Here’s my favorite treatment to prolong the life of cut flowers. I dissolve an aspirin tablet in the water as a substitute for plant food.
My husband buys me a single rose for different occasions and an aspirin in the water lasts for about 3 days. I change the water and add another aspirin. My flower stays like new for about two and a half weeks.
I can persuade cut flowers from the supermarket to last close to a month using this method! Jeannie