For the first you might have waited for the rose to be in the sun and bright and shining, now the background is bright and shining and makes the flower look a little dull. Or you might have "done the dance around" the flower to find a POV that would have offered you a darker background than the flower.
For too bright light is not always the wisest choice, either, since bright light gives you deep shadows. The other two photos are a good example for that. You got some hot spots on the flower since the range from brightest spot to darkest is too large for the camera to expose right. (Or you would have needed to deliberately underexpose to avoid the hot spots). I feel that your focus is not the best in both of the last two.