An unusual bumblebee

I first saw this bee two years ago, and it is now a common site in my garden, especially when the Rose of Sharon bloom. It is a bit larger than the black/white and yellow/black bumblebees that are my most common bees. I like the rusty color.

 In the photo below, "Rusty" is settled in, and a black/yellow bee comes for pollen, then quickly leaves.

 They get covered with pollen!