Hybridity as cultural and philosophical concept is very popular in the humanities and design fields today. I propose the value of hybridity as a framework for thinking about design. After signaling the ancient Mediterranean and Roman origins of hybridity in the western world, I make the case here that landscape architecture in particular as a professional design practice belongs, historically and in contemporary terms, to the sphere of hybridity. As one of the most hybrid, complex and ambiguous forms of design, it partners or interbreeds with natural and plant systems, scientific-technological processes, art, architecture, urban spaces, and territorial-geographical systems. As a hybrid, it is also thus one of the most synthetic design practices, in that it often brings most of these dimensions simultaneously together in one work.