I really don't have any experience with guavas only lychee, longan, abiu, etc. but you could probably give it 10-20-20 which is a good fruit fertilizer or you could give 8-28-8 they all work fine! Hope this helps!

I have a white, Madagascar seedless guava. It is a real beauty! It grew up from a route that went dormant after the original tree died several years before. It was very strange really, but I don't look a blessing like that in the mouth,,,,"gift horse," Anyway, I just fertilize it like my other fruit trees, the same as my mango, avocado and citrus. I put a 6-6-6 or a 6-8-6 or so every few months whenever I do my other trees.