Increasing salvia caradonna numbers
I've got a number of salvia caradonna but want it as my staple plant throughout the garden.
I have looked online, and there seems to be a variety of techniques with different authors claiming theirs is 'the best way'.
Taking stem tip cuttings in spring (now), semi ripe in late summer/early autumn or division in early spring seem to be the options.
While I'm sure all would be OK, what are your thoughts on the most efficient/effective method for me to get large numbers?
I don't have a greenhouse, just a cold frame and a garage with a south facing window that's frost free in the winter.