Some Definitions to get you thinking:

Landscape

Landscape is an ongoing project, an enterprising venture that enriches the cultural world through creative effort and imagination and its practice Landscape Architecture is an active instrument in the shaping of modern culture. (Corner, 1999)

Landscape is a process not a product and it is bound into the effects of time and nature, so then the project assumes a role of an open ended strategy, as in a staging or setting up for future conditions. (Marot, 1999)

Site

A site is the point of where the landscape intervention is made, it has no explicit boundaries because of its symbiotic relationships with contextual forms, functions and it's deeply embedded historical and cultural layers. (Shakeshaft, 2009)