The Tropical Fruit Forum

I would also leave the trunk alone. Any decision can be rightly be made in the next several years.  Many trees with the same problem have grown into full developed trees.

Poncirusguy, nice looking container tree.

There are some advantages obtained by utilizing various  rootstocks.  However, especially lemons on their own rootstock is absolutely fine.

I wish you and your trees all the luck.  In zone 8b you have a good chance unless there is one of those terrible extra bad cold fronts

The trifoliate leaves & branches are from the rootstock.    However, you can cut out the trifoliate branches and retain the monfoliate branches from the original tree.  Then top work

Peep, if the soil is well draining then a large container should not be a problem with proper watering.

It was fairly vigorous and easy to grow. 

I have two Shikuwasa trees. The leaves shown in Peep's pictures don't  look like the leaves on my trees.

I had an inground Bizzsrria tree which I got from Lazz.  I had it for a couple yeas, but finally got tired of caring for it, especially as the fruit was not of eating quality. I replaced it with a Red Grapefruit.

Actually, you would have been better off not putting the two inches of gravel in the bottom of the container, as doing so just raises the perched water table 2 inches higher in the container. 

At those winter temperatures your citrus should do very well.  I do not foresee a problem.

Welcome to the forum.  We are happy to have you as a member. There is a difference for fertilizing a plant that is growing in a container , and one growing in the ground. Plants growing in the ground do fairly well  when using organic fertilizers.  That is because the soil has plenty micro organism to break  down organic fertilizers into usable elements that the roots can use and absorb.  However. in container culture this is not so, because there is not enough organism to break your fertilizer elements into usable elements that the tree can absorb..  Your container trees will do much better using a commercial fertilizer.   Your previous growing method is much of the reason that some of your seedlings died.  I wish you and your tree well.   For kumquats, varieties, only Nagami  does not come true.