Yes. This will serve to clean up the look of the shrub, usually can lead to more flowering (since you are not allowing the flowers to go to seed, ending their life cycle, the plant may try to make more flowers). Also you can prune the shrub a bit, if it is larger than you would like, at this time too. You would not want to prune the shrub any time after early spring, becoz you would be cutting off the developing flower buds. Don't gardenias smell great?

Okay, thanks. One of them is several years old and planted on the woods line where it's very shady and it's becoming quite "leggy". Another (3yo) is doing nicely so far. Am I suppose to prune like I would azalias, after they bloom? These plants usually bloom more than once a year though...at least twice, so I wouldn't want to prune between the bloomings, would I??