Deutzia gracillis. A classic heirloom flowering shrub however I had never used it until the "Triangle Garden" at Bidwell - Potomac - and Elmwood. My selection was based on a sense it could most likely be cut back to eight inches from the ground in the event the garden ever got out of hand, driven over, mispruned, or what not. A plant that can be cut down to the ground and rejuvenated is somewhat mistake proof as no matter what happens, just cut it back and start over. Community and public gardens need such low input management ideas as often volunteer gardeners are caring for gardens.
The Deutzia I can say have performed very well. I believe each and every one have survived, they appear to tolerate drought well, and I think their height and size have about maximized at 24" - although it is possible we received a dwarf cultivar, unlabeled.
I believe these were flowering this season at the end of May.
Landscape designer and Proprietor of Buffalo Horticulture