I have a Fukushu tree that grew with a390 degree bend loop d loop and it is doing fine 5 years later.

Although not a common occurrence, it is also not rare. I don't see any rap around, you tree will continue to be healthy.

I inspected the roots during a repot and didn't see anything unusual. No evidence of any girdling.

I think you have a great healthy pile of roots there.

It is the nutrients, pH, watering, soil mix, light and temps that all need to come together for that perfect growth)

I am sure that you will come to that after all this info)

seedlings often get that little twist. Some worse than others. The rootstock was a seedling and is probably only a few years old. Hope you didn't unpot the plant just to observe the twist.

I've had this tree for a few years, and that twist wasn't there when I got it. I did not unpot it just to see the twist, it was also due for some new soil (it had been in the same 5-1-1 for three years already). That said, I got unlucky and it appears to be suffering from transplant shock now (It's dropped seven leaves in the last few hours, and counting). Can anyone provide some advice on how to treat transplant shock? It's defoliating more and more by the minute.

Hang tight and let it do its thing. It will be good in the long run.

Steve

Graham,

On your original question - it is likely one of two things (I've experience on other plants, but not citrus) - gall wasp or nematodes. Both can cause bulges on roots.

Regarding defoliation - Lemons are the most finicky of patients. Assuming you have a tried and true 5-1-1 recipe, then I would just ensure that your plant is in partial shade for a week. And assuming your medium was properly hydrated prior to the transplant, I would lengthen your period between watering (maybe once a week) and no fertilize until new leaves start pushing..

Looks like a gall, or possibly a burl, but more probably the former, so I agree with Ken. Both are abnormal growths that develop on woody plants. Galls are usually caused by insect or disease activity and present as the type of swelling shown in your images and can develop on branches, twigs, trunks, flowers, or roots of the plant. Galls vary in shape and can disrupt the plant's vascular system, limiting flow of water and nutrients.

Burls form when a plant’s vascular system is disrupted by a pathogen - virus, fungus, or bacterium. Crown gall bacterium is the cause of most burls, which actually alter the plant's genetic composition.

Meet lumpy, a burl growing on a now dead ash tree on some N MI hunting property.

Might as well introduce you to tea cup, too. A maple with a very odd inosculated branch, same location:

Al