Bushing out this lopsieded, and rather straggly, lemon.
I am in the UK and wanted some advice on how I can bush out this lemon tree of mine. It was bought some years ago and I believe is Eureka. Whilst it hasn't thrived, it is doing ok and throws some fruit out each year. It is out all summer, and has wintered before in an unheated greenhouse. This causes the caterpillars to go crazy so I have covered a brick area with polycarbonate this winter and intend to keep it out unless it turns really cold.
As you can see it is fairly lopsided, and very straggly. It hasn't been helped by recent strong winds knocking some brickword down, which snapped one of the main middle branches.
Just hoping for some advice as the really bushy citrus trees always seem healthier, more stable and hold fruit better.