The cherry blossoms at Dumbarton Oaks are in the puffy white stage and haven't yet started opening. They're probably running a few days behind most of the trees at the Tidal Basin. But there are some other beautiful trees in bloom there, including Japanese Plum trees and Tulip Magnolias.
Part of a large, historic estate in Georgetown, the gardens of Dumbarton Oaks have a handful of large cherry trees. So if you're looking for a much less busy alternative to see cherry blossoms, it's a good option. And if you go in the next several days, the Japanese Plum trees are a highlight. The gardens as a whole are still some time away from their springtime prime, but it's a beautiful, calm oasis in the middle of DC.
In the spring the gardens are open Tuesday to Sunday from 2 to 6. More information, including entry fee rates, is available on their website.