These appear within one block on Columbia Heights just north of Pierrepont Street:
I'm very impressed by the care taken arranging the plants and know from personal experience that it's a lot of trouble to keep these things watered and unwilted.
ADDED: Notice how all 3 of the designs have structure to them. There's a rhythm to the colors, a horizontal flow of shapes, and a distinct upright element in the center. The first 2 also have a downward plant, while the third one use the elaborate container to make the lower portion of the design interesting. The ups and downs on the box in the center are particularly dramatic. I wish I'd kept track over the course of the year to see how these window boxes change, but I think they are done and redone with the seasons. I also appreciate the shiny clean windows that reflect the trees and bring even more nature to the picture within the window frame. And note how the first window includes a lace curtain with a leafy design. All those layers! I imagine inside there are plants and flowers and maybe furniture upholstered with flowery fabrics, making the view from the inside perspective even more lush.