There are several reasons why an apple tree does not produce a full bloom:
It is possible that the tree is too young and is just beginning to become reproductive, that is produce flowers. If this is the case, flowering should increase next year.
A young tree may be overly vigorous, spending its energy producing wood and leaves and not flowers. Over fertilization is a possible cause.
Flower buds are formed 10 or 11 months prior to bloom, that is …
There are several possibilities why apple trees bloom but fail to set fruit:
- Apples are not self-fertile and need another apple tree or tree(s) of another different variety (or varieties) so the flowers can be pollinated (by bees, see #2.) and set fruit.
- Apple flowers rely on bees to carry the pollen from one variety to another so the flower(s) can be pollinated and the fruit can set and begin to grow. Both domestic honeybees and wild pollinators (bees, wasps)