I snuck out of NPR the other day long enough to spend an hour in the glassed garden created by landscape architect Kathryn Gustafson at the site of the Smithsonian American Art Museum and the National Portrait Gallery.

(Read this Washington Post article if you need the backstory on this just-opened mega-expensive renovation).

A couple of l.a. friends who are Gustafson fans insisted I check it out. And how! There's just about nothing I love more than a hardscape with "walkable" water (e.g., rills), and a sizeable
part of this courtyard's floor is covered in an inviting liquid veneer.

Children play in November 2007 at the Robert and Arlene Kogod Courtyard in Washington, DC, with its
Tim Sloan/AFP/Getty Images

The courtyard covers nearly two-thirds of an acre and is no easy thing to photograph, but here you can see a section of the fluid floor and much talked about undulating roof. The latter, a source of considerable controversy, was designed by British architect Sir Norman Foster.

I was particularly relieved that the plantings, liberated from D.C.'s overwrought Z7 cliches, included not an inch of liriope. Instead, Gustafson used black olive trees, several huge ficus, a few species of temperate ferns, and a smattering of my pittosporum friends from Down Under (I might have spec'd Pittosporum 'Silver Sheen' with its silvery leaves and black stems but she didn't ask).

The big picture - anchored by huge marble planters - is a great success. "For all its scale," says Post writer Adrian Higgins, "it has a real tranquility". To be on the safe side, though, I'd get there before or after school.