I live in NC (zone 7a) and I've had my rhodo for about 4 years. Last September/October was very mild & warm and my rhodo re-bloomed A LOT. I had never heard of this happening before & didn't think it was possible; have any of your rhodies done this?
I had a Wissahickon do that a couple of years ago. Not a lot like yours but there were blooms in the fall. And it was a very puny plant at the time. Don't know why.
A couple of mine do that often. Winter of 11/12 on bush bloomed most of the Winter.
There are early season - late season and even slow developing bloomers. I have an azalea that bloomed for months this year. Yes, it was only putting out a handful of blooms at a time but I was always pleasantly surprised to see it week in and week out.
If you consider the Encore series of azaleas, it should come as no surprise to see repeat blooming rhodos. I myself have a NOID purple lepidote rhodo that sits against a foundation and gets morning sun that usually puts out blooms every fall/winter, it also turns a beautiful plum/sangria in the winter.
Several of my rhodies bloom every Fall( I have over 600). The real trouble is that this lessens the Spring Show