I really enjoy this photograph. Its clean, its crisp and simple. And well, just over all very appealing.
The blue and pink contrast is perfect. And its not so contrasted that it hurts the eyes. The blurred background with the other pink cosmos in the back makes the photo a lot more interesting then if you had chosen to have the only the sky or a bush as the background instead.
I have a problem with watermarks that take up an unnecessary amount of space, unless totally needed. Your watermark though, is very simple and subtle and doesn't draw the eye away from the actual photograph.
So overall I really don't see anything wrong with this photo and I find it a very simple yet beautiful photograph!