Over the past ten years the preservation of mid-century architecture has become a cultural fixation. If a house by R.M. Schindler went on the market today, a five-alarm rescue operation would follow. If anything, architects like Richard Neutra and Paul Rudolph carry more cache today than when they practiced.

Their contemporaries in landscape architecture? Not so much. How many of us have even heard of masters like Dan Kiley who designed the Miller Garden in Columbus, Indiana (photo above)?

Of the more than 80,000 properties on the National Register of Historic Places, fewer than 1,900 have an element of landscape. The irony is that mid-century architecture tended to emphasize the indoor-outdoor aspect, but preservationists largely ignore the outdoor portion of the sites.

Why do Americans value buildings, but not landscapes? For whatever reason, we tend to see open space as a blank spot waiting for development. For too many of us, designed landscapes means dog runs, cafés, and skateboard ramps. It's hard to make the case for saving Modernist landscapes like the NationsBank Plaza in Tampa (above) because they depart from the convention of the pretty, pastoral scene fixed in our minds by Frederick Law Olmsted.

If landscapes are now claiming a place on the preservation agenda it's due largely to Charles Birnbaum, founder of the Cultural Landscape Foundation, a group dedicated to saving public plazas, private modernist gardens, estate grounds, and historic parks. Birnbaum acts as the James Carville of landscapes, swooping into cities across the country and organizing grassroots campaigns to save under appreciated sites like Heritage Park Plaza in Fort Worth, Texas (above).

Landscape preservation is one of the few fields to have benefited from the economic downturn. As the pace of development slows, Birnbaum gains time to muster support for places like grounds of Bell Laboratories in Holmdel, N.J., which Eero Saarinen designed in the late 1950s. "It is an opportunity for research, documentation, potential designation, deeper and more thoughtful planning and analysis," he told me this week.