Change the background of my photo in a realistic manner

The task is to change the background of the headshot to the leafy background. This will be used for professional purposes so it must look realistic (i.e. that I'm outside, in front of a bush). The fact that it must look real is the most important aspect of the task. For example you might need to edit lighting, shadows or anything else you find appropriate.
I may be able to get alternative photos if these photos are not suitable for the task.