Landscape design may seem intrinsically sustainable, but this is by no means a given. To encourage the application of sustainable design principles to landscapes, the American Society of Landscape Architects (ASLA), the Lady Bird Johnson Wildflower Center in Austin, Texas, and the U.S. Botanic Garden in Washington, D.C., are jointly working on a new green rating system called the Sustainable Sites Initiative.

Designed to complement the LEED rating system for buildings, Sustainable Sites will measure the ecological aspects of public, commercial, and residential landscapes. To develop the system, more than 30 experts from nearly a dozen stakeholder groups—including environmental organizations and landscape architecture firms—have identified sustainable practices for soils, hydrology, vegetation, human health, and materials. The U.S. Green Building Council (USGBC) has agreed to incorporate the findings of the initiative into future versions of LEED.

“This was a situation of great minds thinking alike,” says Nancy Somerville, executive vice president and CEO of ASLA. “A lot of our members began raising the issue that the LEED system was very building-centric. With their prompting, ASLA started some conversations with USGBC about filling the gaps.”

As with LEED, the Sustainable Sites program is designed to be voluntary and incentive-based. It will identify a range of steps that designers and site managers can take to improve the sustainability of their landscapes. To prevent water pollution and protect against erosion, for example, the stakeholders recommend installing a water-infiltration system such as a rain garden or vegetated swales. Sustainable soil management could include soil reuse and the addition of compost.

“We want people to understand the true value of landscapes,” says Heather Venhaus, an environmental designer with the Wildflower Center and project manager for the initiative. “It goes beyond just cutting down a tree, grading a property, and then replanting vegetation. It's about how landscapes support our lives, sequester carbon, and mitigate the destruction of development.”

The initiative will publish its first interim report (which will be available for download from its website, later this month, followed by a public comment period. After further refinements and comment, a final report is expected by spring 2009; it could be a stand-alone product or incorporated into LEED, Somerville says. The participating groups are also working on a series of pilot projects to showcase the efficacy of the rating system under real landscape conditions.

“We want to take the good work that's already been done by USGBC and others on buildings and look at the complete picture with sites,” Venhaus says. “This is about how landscapes can be repairing and restoring and regenerating.”