proconpictures, Inlakechh - You are both right about the “blur” effect - the elements are still roughly cut with a soft brush eraser. I do that while deciding on the composition and what elements I’m going to use because cleaning up all the trees and leaves is a bit time consuming.
Right now only the 2 big trees are properly cut (although they still need a bit of patching here and there).
About the scale - do you mean the scale of things in general or some particular element? I did mean to have abnormally large “alien” trees and plants. The “ordinary” flowers and ivy were going to be a more normal size. I guess they still look too big for the relative distance, huh?
At the moment I have overlay, multiply, screen and, I think, hard or soft light layers. I’ll try further experiments on that. 
Thanks for the crits and tips, guys. 