This is really a two-part log; the first set of photos here were taken about a month ago, when my May Night salvia had finished its first flush. The bright blue blossoms had mostly faded, so I cut them off just above where new blooms were emerging, to encourage the plant to create more flower spikes.
But waste not, want not — instead of composting (you can also just leave right under the plant, to break down in place), I saved them to press for art.
You can get flower presses dedicated for this kind of thing, or follow instructions online to do it quickly with paper towels in a microwave. But I kind of love the slowness of just putting them in a book, piling some other books on top, and sticking them in a corner for a few weeks.
I opened it today and they’re all ready — I’ll probably use most of them soon to make either greeting cards or resin art (bookmarks, probably, given the shape).
Some flowers I press, I sugar and use for decorating sweets, but ornamental salvias aren’t generally considered edible — they’re probably not poisonous, but not tasty either.
One source says: “Most of the ‘answers’ say “only Salvia officianalis is edible” or “the leaves of these 6 well-known species are edible” (pineapple, chia, fruit-scented, greek, hispanica, lanceolata). I’ve been eating leaves and flowers of S. coccinea (texas red sage) fairly regularly for 13 years and its not on any edible species list. I’ve also eaten some S. splendens leaf and flowers, though not regularly. I know that many highly-bred flowers or variegated plants can produce novel compounds that are either harmful or unrecognizable to our digestive system. Hibiscus flowers being a good example (only the traditional single flower variety is safe/tasty).”
https://permies.com/t/108041/leaves-Salvia-species-edible
Personally, I wouldn’t risk eating flowers (or feeding them to guests) unless they’re on a list of known edible flowers.
The ones I don’t use for art soon, I’ll store for the future — right now, I’m using a big binder with plastic sleeves, but it’s starting to get pretty full — I might have to graduate to a different storage system. The garden is generous. 
