Please do not divide the roots. It has not been determined if there are active nodes on the stem above the tubers, but it is very unlikely the tuber and the root below have any nodes which will sprout stems.

You can root cuttings from rapidly growing top growth, but you will have to wait. Good luck harvesting seeds. You would stand a better chance to get seeds if you were in California or another Mediterranean climate.

Thanks, I won't divide. I did get seed last year but discarded them because of other salvias nearby. Cuttings seem like the way to go.

When I lived in Seattle, I grew S. patens and always got lots of seed. I seem to have heard that stem cuttings don't form the tubers and thus don't make reliably hardy plants, but mine didn't make it through Seattle winters most years anyway...