This has been a good winter for overwintering Salvias that form tubers. In fact, some of these have eyes on the tubers that are sprouting. Up to now, I've assumed that one needs to have some viable stem with nodes on them to get sprouting.
So far, I have Salvia stolonifera (first image) and S. lineata (second image) showing budding eyes with stolons beginning to emanate. I've also included images of the new sage, S. serboana (third image - the label was made when I thought this was S. vitifolia). The last is more tap rooted as well, indicating it has adapted to a soil with deeper humus. The first two indicate they might prefer a looser, shallower soil, more like a scree.
This means that it may be possible to overwinter these sages as tubers stored in media like perlite or expanded shale/slate. I've done this already wit tubers of S. clinopodioides, and it should work wit S. patens as well.
You can learn a lot by studying the forms and habits of all the plant parts.