The healing power of green. One of the most wonderful concepts that Hidelgard von Bingen gifts us with is a term not used by any other theologian: viriditas, or "greening power." She speaks eloquently about the "exquisite greening of tees and grasses," of "earth's lush greening." She writes that all of creation and especially humanity is "showered with green refreshment, the vitality to bear fruit."