No, not as tender as citrus and there are reports of them growing in zones colder than yours - see this thread. OTOH, this is NOT an easy clematis to grow and gardeners in much warmer climates (like mine) have struggled with it through several attempts without success. I would definitely overwinter it in a protected location - a garage is fine - and I would cut it back hard.

I overwintered Florida Seiboldi in my unheated garage for two winters in a large pot. it did not survive the third winter. Such a pretty bloom.

I bought my florida Viennetta about 10 years ago. It is supposed to be more hardy than Sieboldii, but I don't take the risk. During the winter it stay in the garage. Every 2 years I take it out of the pot, cut the roots in half and change the potting mix

Thank you all for responding. Just to be safe, I brought the pots indoors. THe plants are still very small and young. I will plant them on my south facing walls this spring. It is usually warmer than the rest of the garden. I agree the flowers are so pretty and unique. Neptune, your specimen is incredibly gorgeous!

Neptune, that's gorgeous! Do you know of a solid color clematis that is closest to the purple of Veinnetta? I'd like to put the two together. Thanks, Lisa (S CA)