Information on Wild Mayhaws?

I hunt deer in northeast Florida and have mayhaws growing next to a drain where I hunt. I repeatedly see that the fruit is supposed to turn to a red color yet the ones where I hunt don't seem to do this. Is there a reason for this? Are they different from the norm? Note; the fruit taste like a small apple, really no bitterness. Some of the trees have long thorns and some don't.

I guess the question is, is this normal for the species?
I also intend to fertilize the trees and read that a 5-10-10 is recommended. I was thinking a 10-10-10 in lieu of the other (probably easier to get). I also read they like a neutral soil, yet today I read they like an acid soil? Which is correct? Your thoughts. Thanks

By Tom