What is eco-phenomenology? This paper argues that eco-phenomenology, in which are folded both an ecological phenomenology and a phenomenological ecology, offers us a way of developing a middle ground between phenomenology and naturalism, between intentionality and causality. Our grasp of Nature is significantly altered by thinking through four strands of time's plexity - the invisibility of time, the celebration of finitude, the coordination of rhythms, and the interruption and breakdown of temporal horizons. It is also transformed by a meditation on the role of boundaries in constituting the varieties of thinghood. Eco-phenomenology takes up in a tentative and exploratory way the traditional phenomenological claim to be able to legislate for the sciences, or at least to think across the boundaries that seem to divide them. In this way, it opens up and develops an access to Nature and the natural, one which is independent both of the conceptuality of the natural sciences and of traditional metaphysics.