I have two gardenia plants that have done well in the garden for many years. I recently noticed many yellowing and browning leaves. Upon inspection, it appears that some of the gardenia buds had turned black and there are spots on the stems. Some stem tips were black. I removed those and all of the discolored parts, but it seems clear that the whole plants are sick.

A couple of years ago, I noticed what appeared to be sooty mold on many of the leaves of one of the plants, and to a lesser degree on the other plant. I tried to clean it off with water and cloth and get rid of the aphids I found with soap and water. After that, the plants seemed to be doing better. Now I'm thinking I didn't do enough.

Is there anything I can do for my gardenias?

yellow and brown gardenia leavesspots on gardenia stems

1 Answer 1


It looks like your gardenia is planted up against a concrete foundation for the wall? Problem is that as soon as the roots get close to the concrete they will consider this a poisonous environment and be unable to support the plant; gardenia requires acid soil and the soil close to the concrete will be alkaline. Your bush looks rather mature, so perhaps the other roots have run out of free space to roam?

Foundations usually run quite deep to ensure stability, so the wall could run several feet down. See if you can probe down to see how far the wall extends. You might consider inserting some kind of sheet metal between the gardenia roots and the wall, although with rain and irrigation the soil at some depth become alkaline on the wall side. With a neutral separation layer, try to acidify your soil again - you may find the gardenia will thank you for it. Consider getting a soil test done, and consult with your local experts to see what kind of fertilizer will help acidify your gardenia environment without giving the plant too much of shock.

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