I also second JAR Jardenia, an intense, realistic gardenia with the proper mushroom note. Regrettably $$$$, and only available in Paris and NYC. Perhaps not exaclty gardenia, but similar in feel, is Les Nez intensely luscious Manoumalia.
I have high hopes for Lutens Une Voix Noire, but have not smelled it yet.
I've got a sample of Fleurs de Gardenia from Creed. I know it's slated for woman, but I like it and have been wearing it around the house, the edge of feminine at the opening, but dry down very doable.
The gardenias are in bloom down here all spring and half the summer. I'll often pick one, crush it slightly, and put it in my shirt pocket. SOTD. No bottled artifacts needed. By September, I've had my gardenia fix. The fragrance lasts for a few days.