The girl's picture (drawing) would look strange next to a real-life image as it is. In order to integrate them properly, I will change the flowers for them to look like a painting. To do this, I go to "Filter"-"Artistic filters" and apply the filter "diluted colour" to the image. As a result, the flowers look as if they were painted with a regular paint brush.
With the eraser tool, I remove the left overs of the picture I won't need, keeping only the branches with the flowers. I have also reduced opacity. I did this so they don't stand out, but rather be a backgound for the girl.