a scene in the books that states that Sam would want to create a garden if he had the Ring

You know, now that you mention it, it's very possible that this is mentioned in the books and I've just forgotten about it -- that would explain where the scene in the cartoon came from!

In any case, it's fascinating to think about. And I particularly love the way your ficlet transforms Sam's love of nature and gardens into this wild vision that's less like Hobbiton and more like the Romantic sublime.