Who was the most important landscape architect of the 20th century?

For me, the choice is between four great landscape architects:

• Ian McHarg (1920-2001) had a major influence on landscape and environmental planning through his book Design with nature and through the innovative projects described in the book. He continues to inspire work on GIS-based planning, landscape urbanism and environmental assessment. McHarg probably has the widest name-recognition of any 20th century landscape architect and received the US National Medal of Arts in 1990.
• Geoffrey Jellicoe (1900-1996) was an innovative designer, a distinguished historian, an imaginative theorist, a founder member of the ILA and the founder of IFLA.
• Dan Kiley (1912-2004) was an inspirational designer and a leading exponent of modernist landscape architecture. Kiley received the National Medal of Arts in 1990.
• Roberto Burle Marx (1909-1994) was an artist, an ecologist and the equal of Kiley as a modernist landscape architect.

The answer to my question turns on how ‘important’ is interpreted. As designers, the world rates the achievements of Kiley and Burle Marx above those of Jellicoe and McHarg. As an environmental planner, and in book sales, McHarg comes out on top. But as an all-rounder with significant achievements in design, literature, planning and institutional creativity, I see Jellicoe as ‘the most important landscape architect of the 20th century’. He also seems to have been the kindest and most generous – though I only encountered the other three as lecturers.

Jellicoe made seven key contributions to the landscape architecture profession:

1. his many books shaped the history and theory of landscape architecture – most notably his Studies in Landscape Design and his history of the Landscape of Man
2. his personal generosity, in passing on jobs, helped many of the landscape architects who became established in the 1950s, including Sylvia Crowe, Brenda Colvin, Peter Youngman and Derek Lovejoy
3. he anticipated the principle, now associated with landscape urbanism, that urban design should rest more on landscape architecture than on architecture or engineering
4. he was a brilliant teacher
5. he helped found the Institute of Landscape Architects (ILA) in 1929 and was our president from 1939-1949. Through his advocacy, Jellicoe made an enormous contribution to establishing the UK profession
6. he was the founding president of the International Federation of Landscape Architects (IFLA) in 1948

Who is shaping up to be the most important landscape architect of the 21st century? Comments welcome.

See also: Geoffrey Jellicoe videos