Someone asked me that question this week and the answer is just not a short one. I checked out my favorite plum trees in Phoenix (Oregon) last weekend and there are no plums on them this year. There are no Service Berries either but that is because the City has cut the shrub off at ground level. How disappointing.
The most likely reason for no fruit is this climate we live in. There were a lot of late spring freezes this year and it only takes one of the right severity when the flower buds are forming, to kill them. No flowers, no fruit. Or it may have been that the spring was too cold for the bees to be out. I have noticed that there doesn’t seem to be nearly so many bees in my garden this year. Fruit trees are insect pollinated, so, no bees, no fruit.
If the tree is an old tree then it could be that it’s reached the stage where it won’t fruit well anymore unless it is pruned. Pruning a fruit tree is very beneficial to the tree, but it must be done correctly and how to do it is the subject matter of many books. If it has been pruned incorrectly then that could also lead to no fruit.
Another possibility is that the tree was grown from a seed. The fruit trees that are sold commercially are all grafted. This means that a shoot from a known apple variety (a scion) is attached to the living stump of a different plant (the rootstock)—usually a hardier variety or a dwarfing variety, or both—and the shoot develops into the trunk, leaves and fruit while the roots remain those of the rootstock. The main reason that fruit trees are grafted is so that you will get the variety you want, but it is also done to dwarf the tree if you don’t have the space or inclination for a full sized tree. Since seedlings are grown from seed and seed is the result of sexual reproduction in plants, you can never really know what type of apple you are going to get, or how reliably the tree will set fruit. And you have to wait a LONG time to find out! For those with patience this is still the way that new apple varieties are developed, and some seedling trees can be wonderful trees. Often though, they don’t fruit well or reliably.
Then there is the ‘every other year’ fruiting phenomenon. Most fruit trees, if left to their own devices, only produce a large crop every other year. This is when the gardener has to step in and try to change the balance. On the years when the tree sets a huge crop, you will need to ‘thin’. If you don’t then the tree will try to ripen all those fruits. They will end up small, less juicy and flavorful, and weigh the branches down enough to possibly break them off. The tree will try to do a little thinning on its own and drop some of the immature fruit, but it doesn’t drop nearly enough. Gardener intervention is needed! If you don’t thin, there is no room for next year’s flower buds to develop, and so next year there will be very little fruit.
It could be that you have a grafted tree, and it wasn’t frozen and the bees were all out, but that you only planted it a couple of years ago. Usually it takes 3-5 years for a dwarf tree to begin bearing fruit and 5-7 years for a standard size tree to bear fruit. These numbers were developed for fruit growing regions like the Rogue Valley, not for marginal areas like ours. If the range is 3-5 years, I would expect to wait at least 5 years here. Our winters are much longer and summers much shorter (and cooler) so the trees just don’t have the time to grow that they do in a milder climate.
So, in a nutshell, I have no idea which of these conditions is responsible for no fruit this year. It could be any of them, or a combination of them. I hope this doesn’t discourage you from planting an apple tree though. Home grown fruit is like no other!