I had the two plants at the top growing in my yard but two new bushes came from the roots of the white one. Each one of them produced a different variation. I guess it is Mom, Pop and the two children. I have no idea how this happens.
Just beautiful - one of my favorite plants - I have a white one like the lower left in your photo. It was covered with Japanese beetles on it this year, but still flowered well.
Spontaneous mutations I guest