False Aralia Dropping Leaves

Question:
I am completely stumped about what is happening to my very big (and previously healthy) False Aralia. We have had this plant for about 5 years. It has never been repotted. It is in a big 20″ diameter pot. When we got it, it was about 5 feet tall already. Now it is about 8 feet tall but all-of-a-sudden is losing it’s leaves. It has dropped the newest, largest leaves first (from the top, then the whole stem drops off the trunk. Soon, I will have one bare trunk – which was previously the largest and healthiest. Some of the leaves are a little brown on the tips and slightly yellow.

My husband added some soil to it a year ago. It was regular potting soil but had been sitting around (opened) outside and I wonder if it had a fungus. I am always careful about watering it. We thought maybe it was shocked/stressed (too much sun, too dry) and needs to recover but now I am worried that it could have verticillium wilt (if that’s possible). It has been in the same position in our house since we got it – so that hasn’t changed. I gave it a little seaweed based fertilizer recently hoping that would help. We are having trouble diagnosing it.

Answer:
Your report that your Aralia is losing its newest leaves first and you are losing entire stems are pretty clear indications of root rot. There are other reasons to believe that is probably the case.

A 20-inch pot is larger than it should be for a plant that size. The extra soil around the rounds retains water for too long and will cause the roots to slowly rot and die back. Initially, that may not have been the case as your newly acquired plant was still responding to the ideal greenhouse conditions where it was grown. However over time, large indoor plants begin to grow more slowly and use less water. Thus, it is quite a while before the root rot begins to slowly take hold and even longer before symptoms of root rot begin to appear. Unfortunately, when the symptoms are as pronounced as they are in this case, it is often too late.

The addition of soil – I assume it was put on top of the original soil – aggravated the problem by preventing air from getting in around the roots. Root rot is actually caused by deprivation of oxygen around the roots. Constant moisture and heavy soil and mulch both deprive the roots of essential oxygen.

Verticillium wilt is not commonly found in indoor plants unless contaminated outside garden soil is brought indoors.

Fertilizer or any kind is not medicine and is intended for use only with healthy, vigorously growing plants.

At this point recovery options are limited. Start by removing all excess soil on the surface that is not in immediate contact with roots. Then, allow the top 2 inches of soil below that to dry before adding any water. Add just enough so that the top 2 inches are dry again in about a week. You will need to experiment to determine what the right volume of water is. This weekly drying will allow oxygen to penetrate into the root zone and hopefully counteract the ongoing root rot. This will take considerable time to occur, for the roots to slowly recover and healthy new growth to return. This will be an extraordinary test of your patience, but it is the only solution and it may be too late for it, as well.

Avoid any suggestions to repot, replace soil or add supplements to the soil.

If you post a photo here or email a photo to me at [email protected], I may be able to provide more specific guidance or determine just how severe the problem is. The photo must show the entire plant, including its pot.