Q.What’s wrong with my gardenia?
My gardenia has two main branches at its base. One main branch and everything that sprouts from it is almost completely dead. What should I do?
Certified GKH Gardening Expert
This is likely a severe fungal infection.
Make sure that there is plenty of drainage in the pot, and if there is not, then you may need to drill more holes.
For treatment, since this is in container, you can make up a mixture of 2 cups of peroxide to about a 1/4 gallon of water. Water this in and it should start to recover in a few weeks.
Alternatively, wettable sulfur and dolomitic lime can also take care of the issue.
This article will help you with the care of these shrubs: https://www.gardeningknowhow.com/ornamental/flowers/gardenia/gardenia-plant.htm