Fothergilla species are in bloom right now, and my guess is that the ones below, blooming in Teardrop Park, are Fothergilla x gardenii, as that's the smaller, dwarf species.
Any type of Fothergilla is pretty cool though, due to the unusual flowers. The white spikes are the stamens and there are no petals on the flowers whatsoever.
Fothergilla is native to the southeast United States, is relatively deer resistant and has very few diseases. I have also seen it in Union Square and Tompkins Square Parks, so that demonstrates the plant's fortitude.
It is in the Hamamelidaceae family, and is thus cousins with witch hazel. It would be easy to guess this as the leaves on Fothergilla have that same distinctive spatula-shape, only smaller.