Possesed Flordia Sieboldii

I have had a Flordia Sieboldii for several years that has lived in a container since I reside at the limit of its cold tolerance. Having spent the winter in a cool basement garage, the plant had gone fairly dormant as usual. A watering in February woke it up and it put out new growth. When it started froming buds we moved it upstairs and gave it light and water. Spring came early and warm and the container was placed on our deck. The first bloom looked normal as it opened with white petals. Then this bloom shriveled up without fully developing and all the subsequent blooms have been purple as in the photo. Same plant. What happened? How can the plant abruptly change like that? Any insight would be greatly appreciated.

My experience is limited with Clematis but I know that in general, when you plant or move a potted clematis, the roots should be shaded. For example a real thick layer of mulch, or a location where the roots are shaded and the plant itself gets sun. I have mine planted right next to the deck stairs covered by several inches of leaves/mulch. I also remember reading that the roots shouldn't dry out. Yours also may be adjusting to a temperature fluctuation having spent the colder months at somewhat of a steady temp, and now being outside a wider temp swing..that one is a stab in the dark!
Rj

Thanks, but the plant has been through the same process two or three previous winters, and the shading of the roots or lack thereof is not going to abruptly change the outer flower color from white to purple. It is like someone swapped plants during the night. Does anyone else have any thoughts???

aah, I didn't realize the initial blooms were white. Just re-read. That is a perplexing one!