We have a row of five gardenia bushes. One died about two weeks ago. It looked fine until 48 hours later when it was shriveled and then died. Now the gardenia bush next to it is starting to droop and turn brown. Both plants have been in the same spot for over two years. The third through fifth bushes are in great shape, but I am wondering if there is some disease making its way through the bushes.
Gardenia Bush Dying
Certified GKH Gardening Expert
It sounds like some type of fungus is affecting your shrubs. I would recommend using neem oil. It will treat the fungus with the added bonus of keeping pests away, which gardenias indoors are also prone to. Here is more information: https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm