I'm not too familiar with Bergenia,
especially how it spreads itself around.
But
I'm all
too familiar with Clerodendrum bungei
(commonly called "Cashmere Bouquet", "Glory
rose Bower" or "Mexican Hydrangea")
which I thought might be what you had, just from the description -
this stuff is running rampant in my garden -
... your photo looks like it, too.
Some pictures HERE