On the plant? As a cut flower? Depends on weather lower temperatures flowers generally last longer but that depends on cultivar. When the temperatures are above 70F and winds blowing I have had a plant bloom in the morning and have only one petal left when I got home from work. I have also had a bloom last two weeks during a cool misty period. I consider myself lucky if the blooms on any plant last longer than a week. Thats why peonies and other flowers are there to treasure, the sight and smell and to provide something to hold in our mind to know beauty will be there even if we aren't. Spring and the next flowering season will be here before we know it.