Are the grass and trees somewhat the final look, or just scribbled sketches? Because they look like scribbles.

the grass indeed looks really messy it also looks very flat, this is because you aply even contrast throughout the patch. try using most contrast up close and progressively less contrast the furter away. kind of like what you did in the river. same goes for the enourmous blob of green in the middle. i really like the tree on the right, you gave it's leaves an interesting texture (although it is indeed still a bit messy), this howeverer, makes the tree on the left look really bad in contrast and it's blobs of green are totally pillowshaded.

good luck, fellow dutchman, i can tell by your current skill that you can make this a great piece, just put some more effort into it.