 He designed the coat of arms for the Commonwealth Law Courts in Perth, in 1992.His works are held in numerous collections, including the Art Gallery of Western Australia, the Art Gallery of New South Wales, the National Gallery of Australia, the National Gallery of Victoria, the Queensland Art Gallery and Parliament House, Canberra

Juniper was given many solo and group exhibitions throughout Australia and overseas, including a major retrospective in 1999 at the Art Gallery of Western Australia, Perth.He was represented for many years by Gomboc Gallery.