Pink Geraniums Leaves

How can it be?  Every time I look outside and see my pot of geraniums I am amazed.  The leaves are "turning" bright pink.  And I mean really bright pink.  I've never seen anything like it.  

I chose this variety (which now I really wish I had saved the label marker!) because of the pretty bright pink geranium bloom and 2-tone green leaf.  You can see how the leaves have been all Summer in this photo.  But would you ever expect, and have you ever seen, the leaves turn pink in the Fall?

It is an unexpected bonus in a plant that has bloomed for me for months.  Thanks, Mother Nature!