What do I have to add to a gardenia bush to get rid of yellow leaves? Only one of three bushes has this problem.
Yellow Leaves on Gardenias
Certified GKH Gardening Expert
Yellow leaves normally signal that the plant is under some type of stress. In order to remedy the problem, you must first try to pinpoint the issue. This article should help you with that: https://www.gardeningknowhow.com/ornamental/flowers/gardenia/helping-a-gardenia-bush-with-yellow-leaves.htm
This article may also help: https://www.gardeningknowhow.com/plant-problems/environmental/plant-leaves-turn-yellow.htm