During the last week of September, I took a walk around the Heirloom Garden of the Museum of American History and was filled — once again — with admiration for the Smithsonian Institution’s horticulture division.
The garden — huge, raised planters, all the way around the building — contains a mix of open-pollinated plants cultivated in America prior to 1950. The perennials and annuals are anchored by crape myrtles and a variety of shrubs.
The space is very large, open, and — at the south entrance — crowded with tourists. Still, the beautiful long borders, which were being allowed to fade with fall naturally, offered a surprisingly intimate and even soulful experience.
You can see more Heirloom Garden pictures here.
One would have thought, (so cunningly the rude
And scorned partes were mingled with the fine,)
That Nature had for wantonesse ensude
Art, and that Art at Nature did repine;
So striving each th’ other to undermine,
Each did the others work more beautify;
So diff’ring both in wills agreed in fine:
So all agreed through sweete diversity,
This gardin to adorne with all variety.— Edmund Spenser, from “In the Bower of Bliss”
enclos*ure 
Whenever I am in DC I make a point to visit the Smithsonian gardens. Like you, I am filled with admiration for the work that the Smithsonian does in its gardens. Last time I actually had the chance to have a conversation with one of the gardeners who was working. The gardens are always worth a visit
They are some of the best in Washington. In fact, I’m not sure I can think of any I like better.
I particularly love the Heirloom Garden, the Butterfly Garden, and the Ripley Garden — all in odd spots: walkways between streets, a big planter box; all plant centric; all managing to evoke an emotional response, as well as be edifying.
Congratulations about the big win at Fenway, btw!