Depends how big the apples were when they went in, usually a first year apple won't bear fruit, nor second... how old were they to start? I do not know the age. But they were 6 feet high.
2. obviously this means where are the bees? Sometimes you can attract them, they like blue, they LOVE bog sage, which survives almost anything. Perhaps some borage, queen anne's lace, other things like that to bring them around? Yes we have bees and hornets..we know, we got attacked by a swarm last Sunday my wife and I.
3. water. An apple tree will drop all its babies if there's no water. Were there any miscarriages under the trees? Not a single fruit on the tree or on the ground.
4. frost/water/weather. What was spring like? did frosts hit and kill the flowers? did winds hit and kill flowers? We had one snow this winter only. It was cold, but cold for the south. IT is Georgia, Augusta. It is like an eternal spring for us Canadians...
We have 4 appletrees with one pollinator. the pollinator is tagged yellow delicious and the 3 others are Gala apples. They are all within 150 feet.
They got plenty of water with rain and when the rain did not go for more than 4 days we have a sprinkler system for the grass and brushes that cover the appletrees also.
Thank you