I have had a Clematis growing on a pole near a woodpile and a shed. It has been growing there for about 15 years. It has always been dark purple with tinges of red at the center. Something weird happened this year and I would like some advice from anyone who might know about it, the flower has turned white the center is almost white(kinda like powdered coffee creamer) I was shocked and surprised to say the least. Is my soil lacking something? The white is pretty, but I don't want to lose the plant if there is something wrong with it. The leaves and vines look healthy.

Thanks,

Terri in Ohio