Rhododendron periclymenoides
Thomas Barnes for USDA Plant Database
The National Park Service documents a few attributes of what is commonly called the Pinxterbloom azalea. Some call this small, native tree Rhododendron nudiflorum. By now, you may wonder about the genus name of Rhododendron, if Pinxterbloom is an azalea. The plants are related but differ in the number of stamen. Azaleas, a species within the rhododendron genus, have five to seven stamens; rhodys have seven to ten.
The name comes from the Dutch, pinxter blomache, noting that the flower blooms near Pentecost. This timing is, of course, region-dependant but does reflect yet again, the varied ways that names enter into English. For more on this story, see the excellent Hilton Pond Center for Natural Piedmont History.
Other shell pink native azaleas in the mid Atlantic include the Florida Pinxter Azalea (R. canescens), Roseshell Azalea (R. roseum), and Pinkshell Azalea (R. vaseyi).
I will plant a pinxter this fall. In spring, I hope to enjoy the fragrance that this "honeysuckle" azalea is known for.