I have no idea how to

prune a citrus tree - or indeed any other tree. I don't know how to prune a rose bush either.
I am told the rose bushes don't matter much. You just lop them at the likely looking points. Yes, I know "experts" who make their living out of pruning rose bushes will not agree. I was however given that information by someone very senior in a large, rose growing society. He assured me we could not kill off the roses that easily. It's true. The rose bushes are still alive.
The lavender bushes are still alive too. I hacked out some dead wood last year and they seem to be flourishing. The French lavender is a mass of colour. The English lavender is looking as if it might be too.
But, the citrus trees. We have an elderly grapefruit tree. It lives next to the side fence. That is probably a rather warm spot for it. Then there is the lemon tree we had to rescue and another lemon tree (small) which was given to me. We have an orange tree (also small) and a cumquat tree. We don't eat the cumquats but we do use the fruit supplied by the others.
And yesterday a friend of the Senior Cat, former teacher and now retired priest, turned up. He chopped pieces off the grapefruit tree and the larger lemon tree and then told the Senior Cat,
"They need to be painted."
Painted? I thought the Senior Cat was joking when he told me this but apparently not. The trees are going to be painted. Their trunks are going to get a coat of white paint - so that the heat from the metal fence will be reflected.
I never thought of tree trunks as naked.