Er, depends on the effect you are going for.
If there is wind, and you want to freeze motion, then shoot with a higher shutter speed.
If you want to convey the wind and show the flowers swaying (as a motion blur), then use a tripod and use a slow shutter speed (say 1s or so). You will need a ND filter to cut down light and a small aperture to get away with the slow shutter speed.
If you want to take a low angle shot of the flowers against the sky, or do a "portrait" of an individual flower, then select a big aperture.
Just do what you like. The LAST THING I would do is leave my camera in P mode!