They tend not to need much - some bonemeal in spring and autumn seems to be fine.

Oops. I was going to say they are gross feeders and will enjoy a mulch of well rotted manure, plus some sulphate of potash to encourage flowering (and therefore fruit)

I put a little woodash on ours from time to time, and give them a feed of what is called "vegetable and fruit" feed in about March-April (I think this will be the equivalent of Steragram's sulphate of potash). I haven't ever mulched them.

I will look out for that because this year so far I haven't been able to find any sulphate of potash, which would be a lot cheaper!

I'm translating from the Italian - "concimo ortofrutta" which has a high potash configuration, apparently, and if it's available in the UK, I hope it's cheaper than it is here, Steragram!