Help with lemon tree and encouraging new branch growth

Question

I bought a lemon tree at the start of the year, at the time it was healthy and had fruit on it. Unfortunately it then suffered severe leaf drop and branch death. I think it was due to high stress from temperature fluctuations in the office overnight. I don't know whether sunlight also played a role here, it was never in the direct sun but on a well lit North-facing windowsill.

Anyway, I took the plant home in an attempt to stop the march of death and am happy to say the plant still lives, now on a South-facing windowsill. Unfortunately, it only has one branch with life still in it (see photos below). I water it lightly, every 5 days or so, once the top soil is dry, and I have used a citrus tree fertiliser. After the branch stabilised and showed no signs of leaf drop/branch death, I pruned back all of the dead branches, making sure to disinfect my secateurs beforehand.

Over the past couple of weeks new growth has appeared on the branch, with a couple of new leaves and some explosions of soon-to-be blossom. Hopefully all of this is a good sign?

However, I'm worried that I need to encourage more branch and leaf growth - how can I do this? I have read something about pinching/removing buds at the end of a branch to encourage growth elsewhere in the plant? Is this advisable? Is the plant currently putting too much energy into growing these blossoms? As of yet I haven't tried anything for fear of stressing the plant further. I would also like to say that I am quite new to gardening but I'm more than happy to do my homework. However, so far most of my search results have been related to leaf drop prevention (too late for me) and I don't find too much on new branch growth - perhaps I don't know the correct technical term?

Many thanks to any and all advice!

1. Before pruning

[1

2. After pruning

3. Possibly some good signs?

4. Unhappy trunk.

5. The unhappy trunks better side.

Answer 1

I think you have acted wisely so far. Now patience takes over as we wait for signs of buds growing from below the active green branches. Depending on how vigorous the remaining tree you may see some sucker growth from lower down on the trunk. In general the younger higher wood is more likely to contain growing points, but with citrus there is always the issue of low level suckers. As we can see from your last photo there is a clear point where the graft union is located about 9" above soil surface where there is a distinct change in bark appearance. Watch for suckers below that line and remove them as soon as they appear. Encourage any new buds above that line, on the desirable scion wood.

I would say leave the blossoms, but remove any fruit that tries to start up. In worst case the existing green branches will become the source of new buds which will result in an unbalanced shape made worse by the weight of fruit. Try to re-establish upward growth of new shoots. Good luck.