Friend of mine is currently visiting UK and, as she is an avid gardener, she
just got crazy about this clematis and wants to bring it back to Poland with
her and plant here. The question is whether this plant is sufficiently
frost-hardy? We are zone 6 mostly, with winter temperatures as low as -20
to -25 degC. Of course it can and probably would be well covered for winter.
Any pointers?

Regards, Barbara.