Question
I have a 50 year old ornamental orange tree that was starting to drop a lot of leaves. It had not been repotted in a while and so I thought that it might be suffering from root rot as I had read several articles that seems to indicate that it might be the cause.  Let me say that the tree has been inside all summer and winter and the temperature where it sits in my house has remained constant. It also sits in front of a southern set of windows and it just below a southern facing sky light so it gets great light.

I repotted the tree which is about 5 feet in height and 6 fee in diameter in a mixture of 3 parts pine bark/much, 1 part course sand and one part peat moss. This was a mixture that several people had recommended I use.

After repotting the tree two weeks ago, I have notice that it seems to be in shock. All the leaves are droopy and many have dropped off entirely. It looks like it is in desperate need of water, but it was watered well after I repotted it and it has great drainage.

Do I need to panic that I have just killed my 50 year old tree or will it bounce back soon? I read not to fertilize it heading into winter, but since it is looking so sickly, I was wondering if that is a good idea. Any advice you can provide would be greatly appreciated.

Answer
Hi Mindy,

Unfortunately, you have been victimized by some bad advice from some well-intentioned people with mistaken ideas.

Mature potted plants do NOT need to be repotted...EVER. Well-established plants are stable in their existing pots. They may need occasional fertilizing to replace depleted nutrients, but they do not need new soil or larger pots. Repotting disturbs the root system and it is usually done incorrectly by most people.

The potting mix recommended to you is not appropriate for indoor potted plants. Pine bark mulch is often a source of fungus gnats. Perlite is a better substitute for sand because it is more porous. Adding peat moss to the mix was redundant. The bottom line is that the mix recommended to you is too heavy, meaning it lacks porosity throughout.

You mentioned that is has "great drainage." I suspect that means you added "drainage material" to the bottom of the pot. That is an outdated and discredited practice that actually has the opposite of the intended effect.

Hopefully, you did not remove most of the old soil from the original rootball when you repotted. If you did, then you will probably lose the tree. I assume you kept the rootball intact and simply moved it into a larger pot. If so, then you can undo your repotting by taking the tree from its new pot, removing all soil and drainage material you added and put the original rootball back into its original pot. If you are able to do this, then your tree has an excellent chance of surviving the trauma of the repotting.

The larger pot and heavy soil that you used conspire to retain water for a very long time around the roots. That leads to root rot, which is fatal to most plants. That is why I am recommending that you downsize the pot and remove the heavy soil you added around the original rootball.

Why did your tree start to lose leaves in the first place? I don't have enough information, but the shorter days and reduced light often cause established plants to shed some leaves, especially trees that have not been pruned regularly. In addition, growth rate slows in fall/winter due to reduced light, so watering less frequently is also important.

Do not fertilize again until your plant has recovered and growing vigorously once again. Then apply it at half-strength and no more than once per month during the warmer months.

I am sorry that you received such poor advice that has sent you done this troublesome road. Unfortunately, there are too many people promulgating information that is out-of-date, anecdotal or inaccurate. I hope you are receiving my information in time to save your heirloom tree.

I have written an article on repotting that I will email for free to you (or anyone else) who sends a request to me at [email protected].

Please let me know if any of this is unclear or if you have any additional questions.

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Regards,
Will Creed, Interior Landscaper
Horticultural Help, NYC

Visit my website at: A link to HorticulturalHelp.com