Apparently they will only fruit if they are pollinated by a different genetic lineage of tree, so you may need to find a different seed/sapling source if those three came from the same place.
Interesting, I hadn't heard that. They all came from the county extension office but I have no idea if that means they came from the seeds of one plant. It might just be worth getting another one just in case.
I do my part to spread the good word about pawpaw's here in PA. We're somewhat towards the northern edge of where they grow, but they're around if you know where to look, and if you have a good hippie grocery store near you they sometimes get them in (for about a week, their season is very short) this is about the time of year for them around here, maybe even a bit too late, because of work and weather I didn't get a chance to go searching for the this year.
If/when I have some property I'm hoping to grow some trees, in the meantime I'm just kind of scattering seeds into the treeline behind my house whenever I get my hands on some. HOA can't really say anything about it, they're a native plant so they could conceivably just pop up there on their own. If I'm incredibly lucky maybe some trees will pop up and start bearing fruit in a decade or so whether or not I'm still in this house when it happens.
Is there anywhere you can find these to purchase or just to try? I've never had one, but apparently they're rather delicate so they don't make it to market very well. It seems like the most common option is knowing someone with a pawpaw tree.
They make it to farmers markets occasionally, and the trees are very easy to identify and surprisingly common. If you know what to look for, most wooded areas in their range will have some pawpaw trees. They generally only fruit for a few weeks in late September/early October but the good news is you’re right on time!