This happens quite frequently, especially with some of the small leaved varieties such as impeditum. Usually the end of summer blooms are incomplete (lacking a full complement of petals) and very short lived because of the heat. A few varieties have been bred with a second bloom as a goal.

There's nothing biologically mysterious about the process. All rhododendrons form flower buds on the current year's growth. Usually the buds will not open until the following spring, but when weather conditions are right, they open in the fall. This is not really a desirable trait because of the poor quality of fall bloom and the fact that bloom in the spring will be diminished.

It happens all the time with Encore Azaleas (they were bred to do that) and with a few others. A drop in temperatures around the Fall often seems to be the trigger over here. Just wondering krycek1984, which rhododendron variety do you have (or can you post a picture)?

It's a Cunningham's White.

I don't really go for silly things like encore azaleas and highly hybridized stuff like that.

It was so bizarre...I was like OMG look, it flowered! And in August! I thought in my head, well, maybe some of them accidentally flower in the fall, but we are far from fall stil! Crazy!

One of my PJM Elites is flowering, it too started blooming in late August and still has some blossoms. I too thought something was wrong and worried that I would not see blossoms in the spring, glad to hear that this isn't unusual.

Linda

Enjoy the show, Linda. I too saw one blooming several years ago when I visited MIL in the fall in NH. After all, other than say something like "Oops!", that is all we can do about it!!! Hee hee hee!

I saw a Rhodo in flower in early september this year on the campus of Rockefeller University in New York City. I was pretty surprised to see it, but my professor, a botanist, just shrugged it off as a late blooming, which happens to many plants. We still stopped to take pictures, but my cell phone sucks at that.