Outside in a container in Ft Worth, TX area.
Why Do Gardenia Buds Turn Brown and Drop Off Before They Open
Certified GKH Gardening Expert
Do the buds look or feel crusty? It is possible that your plant has thrips. They are hard to see and cause damage to the buds, making it difficult for them to open. This article will help: https://www.gardeningknowhow.com/plant-problems/pests/insects/controlling-thrips.htm
This article will help if you feel it is not thrips: https://www.gardeningknowhow.com/ornamental/flowers/gardenia/gardenia-flowers-gardenia-buds-falling-off-plant.htm