The DC area is full of azaleas. Some yards are an absolute riot of hot pinks and purples right now -- mostly with azaleas bred from Asian species. But there is actually an azalea native to this area, and it's quite showy in its own right.
The name Pinxter actually doesn't come from the color of the flower; it comes from the Dutch word for Pentecost. In this area, the flowers may be looking a little ragged by Pentecost (50 days after Easter). It all depends on the weather and on where Easter falls on the calendar in any given spring. I suspect in New York, where the Dutch settlers who gave the name were presumably observing it, the slightly later growing season makes it a perfect name.
In your yard: Pinxters lose their leaves over the winter, unlike the asian azaleas -- probably a key reason that they're not popular as a landscape plant. But we think they're worth growing. The pinxter we planted here at Natural Capital headquarters (aka our back yard) struggled for the first year after we planted it, but is blooming nicely this year.
In the wild: There are several pinxters along the Valley Trail in the northern part of Rock Creek Park. Our favorite is on a bluff looking over the creek north of Holly St.