Open composition ek?
A few ideas :
(1) Write about your family who loves flower
(2) Write about a girl who is sick, probably has cancer, and wishes to see beautiful flowers outside. A guy came and fulfills her wish....etc
(3) Write about the flower that you love, example : Peony, Chrysanthemum, Hydrangea, Daisy...etc
(4) Write about a flower shop?

Just do it creatively :3