I climbed over the roof
I climbed up to the roof.
(At first I was on the ground and now I am on the roof of the room – actually, I climbed up a ladder to the roof. But how can I make a sentence ommiting the word "ladder"?)
The cat climbed up the hedge of the wall
The cat climbed over the hedge of the wall.
(The cat at first was on the ground and now it is sitting on the hedge of the wall of the yard.)