Here’s a bit of discussion from David E. Cooper’s A Philosophy of Gardens that talks a bit about gardens and nature and those who would have a garden be made of only native plants, a topic I touched on lightly in a previous post:

“Nature” and is cognates are, of course, elastic and ambiguous terms, and not a few debates that have raged among gardeners betray equivocation over these terms. When, for example, William Robinson, the nineteenth-century champion of “the wild garden,” argued that it was natural to stock one’s garden with plants introduced from abroad, his points were that one was thereby “naturalizing” these foreign natives and entering into a less parochial “communion with nature.” In objecting to such introductions, however, his many critics have usually meant that it is unnatural to grow plants that are not ecological natives of one’s country or parish. Again, some debates reflect the different uses of “nature” to refer now the the natural environment that is visible to us, and now the “the essential reality underlying all things” which, according to Monet’s friend, Georges Clemenceau, the great painter was trying to “expose” in his garden at Giverny.

(Cooper 2006: 34-5)