Photoshop.

Before

After

   Here is a before and after shot of a picture I had cloned out one flower and cloned a different flower into several different places. I turned down the white balance in the after photo so the flower would not be so bright and made sure when i cloned the new flowers I kept the reflection in the water underneath them. 

Before

After

  In this case, I cut out the cross country runner and pasted her onto a blank background.