They don't need an acid fertilizer. Any general purpose fertilizer used on other fruit trees should be OK. I tend to use some organic source because it is a very sandy soil here. Or I lightly fertilize several times with regular chemical fertilizer because a dosage that on most other fruits would be fine tends to highly wrinkle my pawpaw leaves for some reason. For the bigger plants I combine the two tactics. I heavily mulch with leaves and then fertilize with cheap chemical fertilizer on top of that. The nitrogen becomes an organic fertilizer in the decomposing mulch.

Thank you gonebananas I'll try your method and just use some 10-10-10 sprinkled around lightly.
Lou

Lou:

I like the part where Gonebananas heavily mulches his trees. That's what I have been doing to mine for years, using stable manure, and have no need for any chemical fertilizers at all around the fruit trees or berries. Mulch breaks down slowly, providing the trees with a continuous source of nutrients and minerals, while encouraging the propagation of earthworms and retaining moisture during dry periods.

The trees do get a little 10-10-10 around the feeder roots when I pass nearby with the spreader while fertilizing the lawn, but that's all the chemical fertilizers they see.

Don Yellman, Great Falls, VA