In addition to the Botanical Gardens (reopening in September 2001), the Sculpture Garden and other places, many gov't agencies and businesses have very nice garden displays. There's a courtyard near my workplace that has the most gorgeous display of hibiscus surrounded by boxwoods. When I saw this in the winter, I thought what idiot planted the boxwoods on the perimeter? They should've been planted in the interior!, and during the winter it does look strange. There is also the Canadian Embassy (along PA Ave) with its terraced side filled with azaleas and (I believe) hemlocks. The Dept of Justice building has some nice looking hostas growing as well. All you have to do is just wallk around town.