Four years ago, I was given a cutting of this beautiful flowering bush by a friend who also doesn't know what it is.
It is a weeping bush that blooms dark pink/fuchsia in late August, early September. It dies back to the ground in the winter and grows vigorously the following summer.
It looks like a type of Lespedeza. Take a look at the picture linked below of Lespedeza thunbergii 'Gibraltar'. Here is one of your pictures to make it easier for people to see:
