If students are going to be asked to write about the landscape, they should also be reading widely about the landscape, and the various influences that combine to create it. One of the authors I've read (and re-read) quite a lot recently is Richard Mabey . He now has a website, with links through to books and other resources. Worth checking out.
A blog to provide ideas on teaching LANDSCAPES & provide support for the GA KS3 Teachers' Toolkit publication of the same name