Perfecting the planting of trees
Question: A few years ago we bought several fruit trees from a local hardware store. We bought a variety of apple, cherry, pear and peach trees, plus a lemon and an orange tree for indoors. We did not expect to see much fruit growing for the first couple of years, so we were happy to see a few pieces of fruit.
Finally, more fruit appeared last summer. But several trees produced different fruit than was shown on the tags at the store. There were supposed to be two kinds of red apples and two kinds of golden or yellow apples, but all four trees had golden apples. I think we might have the same problem with the cherries, but we haven’t seen enough of that fruit to get an accurate assessment. Are the trees planted too close together, causing the pollen to mix and form mutt fruits? Can I move the trees before spring?
Answer: What you are suggesting doesn’t actually happen biologically. But before I explain that, I will tell you what I think happened to your trees. I hate to say this since you’ve already had the trees for so long, but somehow the trees were tagged wrong at the store. They all bear the same fruit because they’re all the same tree. If you look at trees at discount stores, you can find apple tags on pear trees, and so on. If you really want specific trees, I suggest that you get them from a nursery that specializes in selling that tree.
The edible part of a fruit that surrounds the seeds comes from the mother tree. Like a child, the characteristics of the offspring fruit are determined by the mother tree and father tree.
If you crossed an orange and a lemon, the next generation fruit could either be oranges or lemons, depending on which tree supplied the female flower. If you plant the seeds of the crossed oranges and/or lemons, the new tree’s fruit might have a mix of orange and lemon flavors.
Another part of your problem is that the ability to self-pollinate is very important when growing fruit trees. Trees take up a lot of space. Oftentimes the grower wants to grow more than one fruit. If the trees you have require cross-pollination, then more trees — of the same species but different cultivars — need to be planted to take up more room. Every variety of fruit tree pollinates in its own way. You need to be careful when picking varieties to get the best match for the most fruit. Two of the same tree doesn’t help; they must be different kinds.
Few apple cultivars are self-fruitful. Even those that are self-fruitful will bear more fruit if crosspollinated. Crabapple trees may be used as a pollen source. The only botanical difference between apple and crabapple trees is that apple fruit is larger than 2 inches in diameter.
Some apricots, nectarines and peaches are self-fruitful and some are self-unfruitful. Some are also not good pollinators and should be avoided.
Similarly, some plums are self-fruitful and some are self-unfruitful. European and Japanese varieties have different blooming times, which makes cross-pollination difficult.
Anjou pears and Bartlett pears are partially self-fruitful. However, they produce better fruit through crosspollination. Some pear varieties produce fruit parthenocarpicly, that is, without fertilization.
All sour cherries are self-fruitful. In contrast, most sweet cherries are self-unfruitful. And some varieties are cross-unfruitful. Cherry varieties bloom over a longer period than most fruits. Crossings must be taken into account.
Citrus trees used to be mostly self-fruitful, but newer varieties are often self-unfruitful. Seedless citrus trees may produce fruit parthenocarpicly, but if the trees are crosspollinated, the fruit may actually have seeds. To help your indoor citrus trees, use a small paintbrush to pollinate the flowers.