There is brown rust like spots on my standard gardenias. What is the problem here and what should I treat it with?
It could be a number of issues ranging from stem canker to a type of mildew. If you're on well water: occasionally the high iron content in the water will literally stain the leaves. But this article may help you positively identify and correct whatever the issue is: https://www.gardeningknowhow.com/ornamental/flowers/gardenia/common-gardenia-diseases.htm