Jencks became a leading figure in British landscape architecture. His landscape work was inspired by black holes, fractals, genetics, chaos theory, waves and solitons. In Edinburgh, Scotland, he designed the landform at the Scottish National Gallery of Modern Art in collaboration with Terry Farrell and Duncan Whatmore of Terry Farrell and Partners. Jencks other works include the "Garden of Cosmic Speculation" at Portrack House near Dumfries; Designs for Black Hole Landscape, IUCAA, Pune, India, 2002; Portello Park, Milan 2002–2007 (Time Garden 2004–2007); Two Cells – Inverness Maggie's Centre, 2003–2005; Northumberlandia Landform, 2004; Cells of Life, Jupiter Artland, Bonnington House 2003–2010; "Crawick Multiverse", 2006–; Memories of the Future landform and reclamation project, Altdobern, Germany; Wu Chi, Black Hole Oval Terrace, Beijing Olympic Park, 2008; and The Scottish World, St. Ninians, Kelty, 2003, 2010+.