If you ever get to the D.C. area in early May, do the Azalea Walk in the National Arboretum. The azaleas are just about every color, and tended carefully. We were a little late this year, so missed the biggest display, but there was still plenty to see.
I had to de-saturate this one, the color was so intense. Have never seen this color azalea anywhere else.
The Azalea Walk is mostly an informal path through a wooded area, but there’s also a small formal garden.