You seem to be doing everything right. Partial sun, more than one tree.

Here is one fact sheet: (Source )

“The Pawpaw, known to botanists as Asimina triloba, is a small, tropical~looking tree, seldom taller than 25 feet. Grown in full sun, the Pawpaw tree develops a narrowly pyramidal shape with dense, drooping foliage down to the ground level. In the shade it grows tall, with a more open branching habit, horizontally held leaves, and few lower limbs.

Shading for the first~year, and sometimes the second, is normally required, and it is for this reason that Pawpaws are almost always found in nature as an understory tree. Although the Pawpaw is capable of fruiting in the shade, optimum fruit yields are obtained in open exposure, with some protection from wind (on account of the large leaves). Plant at least two trees for fruit production, to ensure cross~pollination.

Some Pawpaw patches never fruit, because all the trees are actually clonal root sprouts from one original tree. In such cases, the patch may be made to bear fruit by planting new trees in and around it, thus providing cross~pollination. Little Pawpaw trees coming up in a patch are usually root sprouts from larger trees, and do not have a sufficient root system of their own. This is why Pawpaw trees dug up in the wild rarely survive.

Perhaps because you are on the coast, the trees are getting salty breezes? Is there an arborist or nurseryman in the neighborhood whom you can question?

@gailcalled A Certified Arborist definitely could help me. Their time is isn’t cheap though. I think that I’ll ask the nurseryman who sold me the Pawpaw trees if he is still in busyness. Thank you.

I don’t know if it is the same type or not, but here in Australia there are male and female pawpaws and of course only the female bears fruit. Maybe your tree is a boy!

I just had some pink pawpaw and that was really good. The plain old golden variety I think is tasteless.

@rooeytoo I’m envious of your Pawpaw trees. I have 6 Pawpaw trees planted about 2 meters apart. So far there are no signs of and flowers/blossoms forming (male or female). I guess that I’ll just keep waiting…..

@gondananlon: Perhaps the climate difference between @rooeytoo‘s home in Australia and yours in the PNW explains the difference in fecundity. (business)

People pick lemons and oranges off their trees in S. Cal and Florida, but we have not luck in upstate New York. We can grow banana trees but only for the foliage.

@gondwanalon I think it’s too cold for you where you live. They are tropical trees. I have one about three-years old, and have had fruit, but no good came of the fruit. The fruit fly got into them. I’m in Perth, Western Australia and here we have a climate similar to the Mediterranean countries.