Orlando's first love is nature. When she changes gender and needs to get back to the basics, the first thing she does is travel with a gypsy band to Italy to live amidst the mountains and fields. Nature is Orlando's touchstone for what is important in life. Her struggle as a writer is to find the language appropriate to represent it. Orlando observes early on that green in nature and green in literature are two different things. This distinction, in Orlando's world, proves to be a bad one. She wants to make real green and literary green as close as they can be, using poetic language to evoke what nature is like.
Literature and nature are completely at odds with one another in Orlando.
Nature is a safe haven for Orlando until she realizes that it cannot engage with her about literature.