Bought this gardenia just a few days ago. Noticed some leaves looking dehydrated, so I watered it immediately. Then I kept watering, bottom watering, even added iron sulfate… but the yellowing just kept spreading. Now it looks like this.
What went wrong? Overwatering? Shock? Something else? Any last resort tips before I lose it completely? 
Gardenias are so dramatic, sorry yours is struggling 
I had the same issue — yellow leaves no matter what. Turned out I just couldn’t get the watering right.
Switched to a drip system (RainPoint) and the slow, deep watering made a huge difference. Actually soaks the root ball instead of just running off. No more guessing now.
Hope yours makes a comeback! 
Gardenia are some of the most difficult plant to grow. I had several Gardenia and some of the worst thing to do is to give them to much care. Obviously, your Gardenia had a shock. From where you bought it to your place could be the reason why. Change of temperature or humidity or light may have cause this. Gardenia are very fragile and capricious. Any changes may cause the flowers and leaves to fall.
My recommandation would be to place it under lots of light and live it alone for about a week. All flowers and leaves will fall but the Gardenia is not dead. If your Gardenia wants to live it will grow back leaves in a couple of weeks. If not, well, this Gardenia is not for you. Find another one that will grow for you.
Good luck!
Thanks for the helpful advice! Appreciate you sharing your experience. I’ll try moving it to a brighter spot and see how it goes. Hopefully it bounces back
