AusBonsai

Hey,
First post in a long time.
Here's a lemon I started from seed in 2018.
This was last year, and the following are from today: It's about 50cm tall and the diameter of the trunk base a little over 1cm. The pot diameter's about 20cm.
Currently end of winter here.

Obviously it still just needs to grow more, but is there anything I could or should do right now to improve things for later on?

I thought perhaps I could consider a first trunk chop and getting rid of that mass of roots at the bottom. If I chop about halfway for now, that would leave the bottom four or five branches. My thinking is this will encourage some more low branches, and wont be too violent for now.

Or at this point could I go further and chop just above that lowest branch, which has just a few leaves on it and would become the new trunk?

I was also thinking of potting it up at some point. If I prune the roots a bit, would it be better off going in the same pot again (and perhaps waiting a while before potting it up for more size)?

Cheers,
Josh

It looks very healthy, so probably ready for some work to be done on it. The roots definitely need a prune. If it were mine I would do a trunk chop just above the lowest branch and use that as the leader. Lemons back-bud well and strongly, so you should have some new branches popping from the lower trunk.

I don't have any Citrus bonsai but I have plenty growing in the garden and in large pots, and I don't do any root work until closer to summer. Here I wait until late September/October, depending on the weather as the soil needs to be warm for Citrus roots to recover, so keep that in mind. As RB said, chopping the trunk low should result in lots of new shoots which would give you more to work with in the future and produce better taper in the trunk, and a new leader would give movement.

Good luck!

Matt.

That's not root bound yet. It does have some circling roots at the bottom of the pot but that's always where roots end up first. root bound is when the entire pot is full of roots.
That said, root pruning won't hurt but I agree with Matt S. Warmer weather for citrus roots to recover well so you will have to make that call depending on the current weather in France.

At this stage of development it won't really matter if you cut at the lowest branch or a bit higher. There is so much growth to come that it does not really matter where you cut now provided you have some leaves left. Citrus can recover from bare wood but don't always.

Looks like the temperatures start averaging 10-20 degrees around the start of may around here so I'll leave it alone at least til then.
Thanks!

Did the root prune and prune yesterday. It coincided with finishing a wicking bed so planted it in that.
Cut off roughly that much. Actually went a little further on the trunk, and also cut back a bit more of a big fat root underneath.
Chopped just above the third branch.

I was just going to say it is not the best time of year to root prune citrus then I noticed you are in France. Should be ideal time for transplanting that lemon tree and I think it should love the wicking bed too.