We can solve all your pond problems

Over the past 7 years, people visiting our pond have asked what this plant is.  Its woody stems appear red in the spring and its leaf buds are pink/red.  As they open, the leaves get paler and greener.  These pictures were taken in September when it is "in flower".  

I have always had to say "I don't know what it is.  I bought it on sale at Frank's because it was supposed to like moisture and shade.  It was about 9" high then."

Thanks to Gayle Stevens for finally identifying it as a variegated fallopia.  She said they are available at Wannamaker's.  Thanks Gayle - mystery finally solved.