To be scattered or untidy; to be in disorder (intransitive). Used for places or surfaces becoming messy (e.g., 'the room is messy').
子供の玩具で部屋が散らかっている。
The room is messy with the children's toys.
勉強中で机の上が散らかっている。
I'm studying and my desk is a mess.
いつも散らかる部屋を片付けるのが大変だ。
It's hard to clean up a room that always gets messy.