We have had this indoor Ficus Tree for 26 years now, it was given to me as a retirement gift from the folks I worked with. At that time it was about 4 feet tall and now it’s just a little over 11 feet, branches have a diameter of approximately 5.6 feet. The trunk is about 4 inches at it’s largest part and it’s in a container that is 18 inches diameter and 15 inches high. It’s in a tall vestibule with good afternoon lighting and has been a joy to own and admire.
We live in Pennsylvania, so the weather has turned colder but the tree is in heated space but the days are shorter. To date, very few problems but the past month has seen a constant yellowing and dropping of leaves? In addition, whole branches appear to be dying? We are very concerned and would really appreciate any assistance that you could provide. We water on an approximately a weekly basis but last year we added a water softener which we are concerned might be affecting our tree. Our water is drinkable so the settings are not outrageous but I know that it is different than what it’s use to having.
I’m glad you thought to mention the water softener because that is almost assuredly the cause of the problem. Water softeners add various chemical salts to counteract the naturally occurring minerals that make water hard. Unfortunately, those chemical softening agents are toxic to most plants. It takes a while for the softening agents to build up in the soil and gradually affect the roots and then the foliage. That is why you are only recently seeing the leaf drop.
There is only one solution to this problem and it is not an easy one with a large tree like yours. You will have to flush a large quantity of clear water (filtered, distilled or rainwater) through the rootball and out the drain holes. That flushed water must be discarded and then more clear water flushed through. The more flushing you can do, the better. I suggest you try to do this outside, however temps should be above 40 degrees F. and you should not leave the tree outside for long.
If your tree is too large to move outside, you will have to find a way to capture and remove the water as it flushes through the drain holes. A turkey baster or some other suctioning device may be useful.
Sorry there is no simple solution to this problem. Good luck with it!