Allen ....
I don't know about cooking with it ...
And I don't know the proper timing of a rejuvenation prune for rosemary. In roses, it is usually done as the plant is coming out of dormancy. The rule of thumb is to take some of the old wood out at the base of the plant to encourage new wood to grow every year or so ... it depends on the rose.
The process leaves you with a more vigorous plant and a more long-lived plant. You are imitating fire.
Since I don't know your climate, I don't know if this is the right time for the haircut, either.
Smiles,
Lyn
