[quote='Coatl]
The other option would be to place the cuttings in water until they grow new roots (this may work better).
[/quote]
This is what Ive been doing with my salvia cuttings, and its worked, im terrible at taking cuttings usually, never seems to work, but Im well happy that my salvia took quite well when just putting it in water. I took four off my big one the other day as I didnt prune it properly at the beggining and it keeps growing really big, some stems have snapped off, so Im just starting to cut them when they get like that and trying to grow roots, just in water. Two of the cuttings I took the other day just seemed to wilt straight away, wheras another two seemed to be ok. If you take cuttings im sure minimum size is 12cm.
I dont feed mines that much, but a little bit of nutrients can make salvia grow like mad, I accidently gave it something called formulex and it grew really big, then in turn stems started snapping off etc. My friend told me when repotting saliva to put it close to the bottom of the pot, because salivia naturally grows then dies due to the weight of its stems and leaves, it just keels over and snaps, if you prune it properly though its meant to be ok, which im going to try do with my other cuttings I have.