I have about ten trees in my overwintering greenhouse. All were purchased this spring from various sources, and all received pretty much identical care. In the late summer, two of my trees showed steady decline while still outdoors and continued to decline once moved to the greenhouse. The rest of the trees are doing great, so I don't think it is an environmental issue.

The most severe is a Eustis Limequat. It has been slowly dropping leaves and turning yellow all over. I thought maybe it was a nitrogen deficiency and had been applying foliar fert for a few weeks to no effect. It is potted in the same free-draining mulch/peat/perlite mix I have always used, but I noticed recently that the pot drainage holes weren't quite at the bottom corner of the pot, they were about 1/4" up so maybe it was pooling a small amount of water at the bottom. I cut the draining holes lower and kept an eye on it. No improvement over a week or two.

Here it is when I got it in late spring


This is how it looks now



I finally pulled it out of the pot and it has nearly no roots. Some of the remaining roots look blackened. Is this Phytophthora rot? I saw a few tiny black spots on the leaves. The rootball used to be sized for a 5gal pot and now fit comfortably in a 2gal.


I applied Agri-Fos phosphorous acid spray to the whole tree & roots and repotted into a smaller pot using fresh medium. I'm hoping it isn't too late for this one but I think it will die soon.


The second tree with issues is a golden nugget mandarin. The leaves had been turning yellow from the oldest growth up. The newest growth from this summer is still healthy and green, but this seems like too much change to simply be old leaves dying. I found some mealybugs on this tree two weeks ago and have been picking them off and spraying hort oil every few days. I still find one occasionally but it doesn't seem too serious. None of the other trees have any bugs.



After seeing the limequat roots I got worried about this one and pulled it out of the pot. The roots looked just fine so I put it right back in the pot. Any idea what might be wrong with this one?

On those pictures it is hard to be sure but it seems you are suffering from a hard spider mite attack.

You state the trees are planted in a blend of mulch/peat/and perlite. What is the mulch? I don't see any mixture of large, medium and small sized ingredients in the make up of the medium you have your tree planted in. The medium's ingredients all look small. When a problem is due to a medium that a troubled tree is planted in, the problems usually begin about in the 6 or 7 months or so. With leaves being discarded, and the root system 's failure to develop the problem is surely in the container. - Millet

I don't see any webbing on the mandarin, though there have been some mealybugs as I said. Aren't spider mites visible to the naked eye? I have been looking closely for mealybugs and haven't noticed anything that looks like mites.

The mulch I am using is the generic "Cedar Bark Mulch" in 2cu bags from Home Depot. It is shredded and has small and large pieces but I agree with you that it seems to be broken down quite a lot in the 6 months or so since repotting. I will look for another variety when I repot next.

Hmmm. I have many trees in a medium of 50:50 V/V cedar decorative mulch and peat, some are in a 50:50 V/V cedar decorative mulch and Miracle Grow's potting SOIL (Not Miracle Grow's potting mix). They are over a year old, and still look just about what they did the day I potted the trees up. Decorative cedar mulch that I purchased has pieces from 1/4" to as large a 3". The reason that cedar is useful as an ingredient in a growing medium, is because it is a wood that is slow to degrade. That is why farmers use cedar as fence posts. Cedar mulch can be purchased either as a red or a natural colored product. I buy the natural. Anyway, I don't see any larger wood pieces, or any wood for that matter, in your tree's medium. I suppose red wood could also be used, but would be more expensive. Do what you think best, but if they were my trees, I would re-pot them anew, leaving out the perlite. Wishing the best to you and your trees. - Millet

The pieces aren't as large as I remember. There are larger pieces than found here but they seem to be the exception. I don't have anything good for size comparison in the picture but the square-ish pieces are under an inch.




I am hoping I can get by until spring before repotting with a better mix.

The cedar mulch that you show above is really a lot smaller in size than the cedar that I purchase. One of the main uses for decorative cedar mulch is to put around the base of trees, flower beads and paths and etc. to give the landscape a nice appearance. No where have I ever seen a cedar mulch as small as the pieces you show. Timberline's product looks like they are left over fines. They look so splintery, I think they might be dangerous to use in landscaping where children are around.. - Millet

Yes, I don't think this is a good brand.