A Seattle landscape-architecture firm is one of six finalists to redesign what is being called a neglected area of the National Mall in Washington, D.C., the most-visited park in the national parks system.

Gustafson Guthrie Nichol (GGN), working with architecture and design firm Aedas Architects of New York and Washington, D.C., is competing to redo one of three areas of the mall, Union Square.

"It's fantastic," said Kathryn Gustafson, a founding partner of the Seattle firm. Washington, D.C., is "a city fascinating to work in," she said, "with one of the most-rigorous urban codes we've ever worked in."

Specializing in creating peaceful spaces in urban settings using native vegetation, the firm did landscape design for the new headquarters of the Bill & Melinda Gates Foundation and Seattle City Hall. Gustafson founded the firm in 1999 with partners Jennifer Guthrie and Shannon Nichol.

It also recently won the Smithsonian Cooper-Hewitt National Design Award, one of the highest in the country for landscape architecture. In awarding the prize, judges said GGN "offers special experience in designing high-use landscapes in complex, urban contexts. The landform of each space is carefully shaped to feel serenely grounded in its context and comfortable at all times, whether bustling with crowds, offering moments of contemplation, or doing both at once."

The National Mall, home to 12 monuments, stretches from Union Square, at the foot of the U.S. Capitol, to the Lincoln Memorial, and from the Jefferson Memorial to Constitution Avenue.

According to the Trust for the National Mall, which is staging the competition, the Union Square redesign will be focused on the statue of President Grant.

The National Mall draws more than 25 million visitors each year, and the trust wants to create a space that will accommodate more visitors and be a place for national celebrations, demonstrations and other events.

The park was not built to support that level of use, the trust said, "and, as a result, the National Mall is in need of many repairs." The trust is hoping to raise $350 million for the work.

The competition also calls for redesigns of the Sylvan Theater, on the Washington Monument Grounds, and Constitution Gardens, but GGN did not bid on that part of the work.

The competition is still in the early stages. The competing firms will undergo interviews, and the finalists will be asked to submit designs early next year, with the winner announced in May.

"When you start a project like this, you need to do a lot of listening," Gustafson said of the Union Square project. "It's right at the base of the Capitol, the hot-button kind of site. You have to be very, very careful with it."

Susan Gilmore: 206-464-2054 or sgilmore@seattletimes.com