This depends on the location of the flower and the conditions in which it exists. You could get really creative with a flower planted and growing outside...worms, butterflies, sun, rain, wind, the neighborhood cat, mice, snails, caterpillars...etc.
Inside flowers would experience conversation, music, air conditioning, perhaps not close enough to a light source, household pets, children playing frisbee or football indoors, so many things to consider.
This can be a fun exercise! Have a blast with it! :)
Why not watch the budding and opening of blossoms on fruit trees for a few days? Botanists state that there is a tremendous amount of energy exerted by trees to produce the blossoms which will then become fruit. The transformation of bud to blossom to fruit is one of generation and regeneration. This "naissance and renaissance" could be recorded as journal entries for two seasons, Spring and Summer--birth as a flower and rebirth as a fruit, not merely a bloom that eventually dies, but a thing of beauty and produce.
Think about the natural environment of the flower. Earth. Water. Sun. All of these are essential to its life. I like the suggestion above. Sit quietly outside near some flowers and write down your impressions.
Why don't you take an hour...even 20 minutes and sit on the ground by a flower and jot down what happens. Don't forget that good writing invokes ALL the senses. Head up each one and write what you feel under each of the headings. Take the questions that speamerfam has given you and use those as headings as well.
Once you have your notes start working with them and shaping them into a day in the life type piece.
I often find that my students write better from actually experiencing what I'm setting as a topic. I often take them outside and make them write exactly what they experience and then go back in their own time and look at what mood changes have occurred. They come with some very cool stuff and I think you would too.
Try to use your imagination to write about what a flower experiences by choosing a particular flower. You could be a tulip or a crocus, for example. You might want to consider writing about a flower in the spring or the fall. What effect do those seasons have on a flower? Are you warm or cold? Is it painful to push up through the earth in the spring or to lose all of your "self" in the fall and winter? What makes a flower feel good? Do the bees hurt the flower or provide a pleasant sensation? Are you happy to be picked to decorate someone's dining room table? Or is this an unpleasant occurrence? Do you worry about whether other flowers are more beautiful than you? Or do you like being surrounded by beautiful friends? Those are just a few ideas to get you started!