Almost certainly rhododendron cinnabarinum or possibly a hybrid of that species. Rhododendron questions would be better posted in the azalea and rhododendron forum.

Here's the link:
Azalea and Rhododendron forum

An open habit is typical for rhododendrons of this affinity.

http://www.bing.com/images/search?q=rhododendron+cinnabarinum&qpvt=rhododendron+cinnabarinum&FORM=IARRSM

Also - although problems with it are not apparent in your picture - powdery mildew can be murder on these, resulting in premature leaf loss, even premature plant loss.

Thank you for responses. Seems to fit the description. No signs of powdery mildew. Crossing my fingers.