pruning Russian sage

How should russian sage be cut back? I did not cut a 20 yr. old plant earlier this summer and it is over grown now.
Usually I keep up with it, then cut back in the fall.
Does it grow only from the old wood?

Doug says that first of all, this isn't an edible herbal plant (let's get that out of the way) :-)

In cold climates, it dies right to the ground and regrows from there. So when the plant is dormant, you can cut it as far back as you like.

If you're in doubt, leave 12" shoots to identify where it is in the garden and to give the plant some basic framework for new growth. It will regrow from there.

In warmer climates, it can regrow from living wood above the ground.

But bottom line - when the plant is dormant, you can whack it back almost as much as you like to bring it back into control.