Cut any shoots that have finished flowering down to ground level. In the end, come autumn, they should all be cut down.

The salvia treatment depends on what type it is. Salvia nemerosa should be cut back like Echinacea and Achillea but more shrubby types such as S. microphylla 'hotlips' should only get a light trim in spring...if at all.

Not too sure what you mean by "Montana"

The only Montana i know is a sort of clematis. Wonder if you mean Monarda?

I tend to dead head them and reduce the height by half in the autumn so the remaining foliage affords some winter protection and then down to the new growth in the spring. depends how tidy you want it too look.

I also tend to take the saliva and use some of it for insurance cuttings.

Have to disagree with Badfish re. Microphylla,plant care recommends "cut hard back in early Spring "which is what I will do with mine as they can grow to 90cm(36")x75cm(30"),kerryvw.