I take care of a potted rubber tree at the library. It is always inside and always in the same location although I do rotate it halfway around from time to time. I do fertilize it about 3 times a year and I do not believe that I am over watering. The problem is that over the last couple of weeks it has been dropping leaves (these leaves are turning yellow and have a few dark brown spots on them). I do destroy these thinking that it might be a fungus. It is a large plant, probably 5 foot tall with a spread of 7 foot or more. So what do you think is the problem and what should I do?
Certified GKH Gardening Expert
A number of things could be causing this. This article should help: https://www.gardeningknowhow.com/houseplants/rubber-tree/rubber-tree-plant-leaves-falling-off.htm