There are as many reasons why fruit trees don't bear fruit as there are types of such plants. Worse yet, there can be multiple causes at work simultaneously. What's most frustrating is that many of the reasons can't be detected simply by walking up to the trees and inspecting them. Adding insult to injury is the fact that the problem often can't be solved immediately.
But many of the problems are solvable through good planning. It all begins with proper plant selection, followed by locating your fruit tree in the right spot when planting (including placing it far enough away from other trees, as per label instructions). But even if you get the selection and the location right, there are several things that can go wrong later. Other reasons for fruit trees not bearing fruit include:
- Timing: You may be expecting too much from a young tree or one that had fruited heavily the prior year (a bumper crop can drain resources that would otherwise be available the following year).
- Pollination issues
- Sun and soil conditions
- Improper pruning
Good detective work on your part is needed to sift through this list of potential problems and arrive at the one(s) responsible in any given case. Through the process of elimination (and with patience), you'll eventually learn why your fruit tree isn't bearing fruit.
Age of the Fruit Tree
A basic mistake beginners make is in being impatient. You simply cannot expect the fruit tree you brought home from the nursery last year to bear fruit anytime soon.
On average, fruit trees purchased from a nursery are one to two years old. The plant label they come with may provide a "years to fruit" figure. This figure indicates the additional years the plant must grow before it typically bears fruit. Apple trees (Malus pumila) take as many as five additional years to fruit, pear trees (Pyrus communis) and plum trees (for example, Damson, Prunus institia) six. Dwarf cultivars may bear fruit sooner.
Problems With the Cold
Where you live limits you in terms of which fruit trees you can grow:
- Apples are suited to USDA planting zones 4 to 7.
- Bartlett pears bear fruit in zones 5 to 7, as do Damson plums.
- But you can't grow tangerines (Citrus tangerina) outdoors in those zones; the latter are suited to zones 9 to 10.
You can push the hardiness envelope some by locating your fruit tree in a sheltered area. The south side of a house, for example, usually stays warmer in winter than other spots.
How to Beat the Frost
But it's not only cold temperatures in winter that you must consider. Climate irregularity is the bane of the fruit-tree grower. A warm spell in winter can trick flower buds into thinking it's spring; when cold temperatures return, the buds can be damaged. Likewise, if there's a frost after the flowers open in spring, it can kill them, meaning your fruit trees won't bear fruit that year.
For this reason, smart plant selection includes making your choices based on the time of year a fruit tree blooms. For example, apricots (Prunus armeniaca) often bloom early for fruit trees. In the years that they do so, their tender flowers are left wide open to killing frosts. This is one reason why apples are so popular in cold climates: They're one of the last fruit trees to bloom.
If you're already stuck with an early-bloomer, there's one hope when your fruit trees are in bloom and you hear a frost's coming: Cover your plants with plastic sheets or blankets.
Problems With Not Enough Cold
Cold isn't always a bad thing when trying to get fruit trees to bear fruit. Some types actually need a certain amount of cold. Except for citrus trees, fruit trees have something called "chilling requirements."
This need for cold is measured in terms of "chill hours," which refers to a minimum number of consecutive hours during a period of winter when the temperature ranges from 32°F to 45°F. Different types of fruit trees have different chilling requirements, ranging from a low requirement to a high one; for example:
- Peaches: low
- Damson plums: medium
- Apples: medium
- Pears: high
This fact helps explain why apples are grown commercially in Washington state but not in Florida: They need more chill hours than the Sunshine State can provide.
If all goes well, your fruit tree will bear flowers one spring. That's a great step in the right direction: A plant such as an apple tree can't bear its fall fruit until it has first had a spring flowering. But you're not necessarily out of the woods yet because there's still the issue of the flowers being pollinated successfully.
Most apples and pears must be cross-pollinated. This means that pollen (the male element) must travel over from a different variety to fertilize the female flowers of the tree you want to bear fruit. There's a lot to get right in cross-pollination:
- You must remember to buy a pollinator.
- It can't be just any different variety: Consult nursery staff to learn which pollinators are compatible.
- Unless the wind blows just right, the pollen must be brought over by bees. If cold weather, heavy rains, or strong gales keep bees away, the flowers may not get pollinated (another argument in favor of planting in sheltered areas).
But some fruit trees are self-fertile, including apricots and certain kinds of plums (like Damson): They don't need a different variety to be present to serve as a pollinator.
Cherries That Are Hardy, Self-Fertile
As with other types of fruit trees, not all cherries are created equal: Some are easier to grow than others. Tart cherries (Prunus cerasus) are more cold-hardy (to zone 4) than sweet cherries (Prunus avium), which can be grown as far north as zone 5. Sweet cherries (such as Bing) are the eating cherries you find in the produce section; tart cherries are more likely to be used in jellies.
Another feature that makes tart cherries easier-to-grow plants is that they're self-fertile. Among the sweet cherries, only Stella is self-fertile.
Sun and Soil Conditions
All of the fruit trees mentioned here belong to the rose family, and many are in the Prunus genus. These latter are known as "stone fruits" because they have a pit inside their fruits. Apricots, cherries, peaches (Prunus persica), and plums are all stone fruits.
Another fruit tree that's a rose-family member is Cydonia oblonga (so is Chaenomeles, but it's an ornamental quince, not usually grown for fruit). Like tart cherries, it's self-fertile.
But we still must discuss some of the other potential problems in fruiting, beginning with sun and soil conditions.
Fruit trees need full sun and won't bear much fruit if located in shade. "Soil conditions" covers a range of issues, including:
- Weed control
Water to keep the soil evenly moist, but don't overwater (few plants like soggy soil). Likewise, correct fertilizing means striking a balance: Fruit trees need to be supplied with nutrition, but overfertilizing causes more harm than good. Excessive nitrogen is especially self-defeating: You'll end up with a bunch of leaves and no fruit. Compost is safest because it's a natural slow-release fertilizer.
Weed control and proper spacing are closely tied to irrigation and fertility issues. Weeds compete for the same water and nutrients in the soil as do your fruit trees. Likewise, without sufficient spacing, your plants are stealing resources from one another. Garden mulch is a great ally both for conserving soil moisture and preventing weed growth.
A common disease problem for pear trees (as well as some other fruit trees) is fungal infection. Fungi can ruin the flowers, depriving you of fruit that year. Ask your local cooperative extension to recommend a fungicide suited to your region and your type of plant. The trick here is to spray at the right time: Avoid spraying during bloom time, since that could kill the bees you need for pollination.
Pruning is important for fruit trees, but prune with a purpose in mind. Your goals are to:
- Develop a solid framework for fruiting
- Remove water sprouts and branches that are crossing, have died, or have become diseased/damaged
- Open up the canopy, letting in light and air
Many types of fruit trees are pruned in winter, but plums and cherries are exceptions: Disease is more likely to enter open wounds on them in winter, so pruning is done in spring or summer. Foster the growth of a central leader when pruning plum trees, pears, apples, and cherries.
There are different kinds of pruning cuts to achieve different ends. Thinning cuts generally do more good than heading cuts when caring for fruit trees. Heading cuts may actually increase the time you spend waiting for flowers to develop, as they encourage growth to go into leaf production rather than flower production.