I and my mom have put our geraniums in the garage and they've survived the winter. We watered occassionally, but just enough to get the soil wet and not during the super cold days. They come back.
And then there ahve been times I've brought them indoors and watered and fed the regularly and they keep on growing and blooming. However, they get super leggy.
To really answer your question...it depends on the perrenial. Some need to rest and go through the winter process. Contact your local greenhouse and ask for specifics.