How to Grow Fruit and Berries in Containers
While growing flowers and vegetables in containers can be a snap, growing fruit trees and berries takes a little more forethought. You need to become familiar with such things as rootstocks, pollination, and climate adaptation. You may need to prune and thin.
Many types of fruits and berries adapt nicely to growing in containers. And plant breeders continue to develop compact varieties especially suited to container growing. Growing fruit in containers has advantages, as well. Most noteworthy is the mobility that containers provide. If frost threatens, you can move your fruit trees under cover for protection. So although container fruit growing takes a little more effort than growing flowers or vegetables, the payoffs are well worth it.
You probably remember from Biology 101 all about how pollen moves from the male part of the flower to the female part, fertilizing it, and causing a fruit to grow. Some fruit trees, like peaches, have compatible male and female flower parts on the same plant — this kind of plant is called self-fruitful. You can grow one peach tree — or other self-fruitful plant — by itself, and it will produce fruit.
Other fruits, including some apples and blueberries, produce more and better quality fruit if they’re cross-pollinated, which means that they receive pollen from another variety. You can grow one apple or one blueberry plant and probably get some fruit, but you’ll get much better production if you have a second, different variety growing nearby. For example, if you plant one or two Bluecrop blueberries, you’ll get some fruit, but if you plant one each of Bluecrop and Earliblue varieties of blueberry, you’ll get a bigger, better harvest.
For some fruits, such as plums, you need a specific variety (usually one that blooms at the same time) for proper cross-pollination. Pollinators carry pollen from flower to flower, or even from one part of a flower to another part. Pollinators are usually bees, flies, or other insects, and you probably have plenty of those in your garden. Even city dwellers will have bees and flies buzzing around, especially if they plant flowers nearby.
Most fruit trees have two parts: the rootstock and the scion. The rootstock is the below-ground portion of the plant. The scion is the above-ground, fruiting part of the plant. The point at which a scion joins the rootstock is called the graft union or bud union. The graft union is usually indicated by a swollen or curved part of the trunk a few inches above the soil level. Below the graft union is the rootstock; above is the scion.
In simple terms, when nurseries grow fruit trees, they bud or graft the scion variety onto the rootstock to take advantage of the best attributes of each plant.
Obviously, the scion produces great tasting fruit — that’s a considerable attribute. But a good rootstock can contribute qualities like adaptation to specific soil types, hardiness, or size control. If grown on their own roots, most fruit trees get huge — way too big to grow in containers. But if grown on rootstocks that keep them smaller, called dwarfing rootstocks, these same fruit trees become ideal for containers. Apples perfectly demonstrate the value of dwarfing rootstocks. A normal apple tree can grow up to 40 feet high. But the same variety grown on a dwarfing apple rootstock can be reduced in size by over 75 percent, reaching just 10 feet tall.
Not every type of fruit is available as a dwarfing rootstock. But, the genetic dwarf fruit tree is naturally smaller. For example, a standard (normal size) peach tree may reach 25 feet high. A genetic dwarf peach rarely gets over 6 feet high — perfect for containers. The number of genetic dwarf fruit tree varieties available is growing. Unfortunately, their fruit isn’t always as good as that of standard varieties, but it’s certainly better than store-bought fruit!
If you have a favorite variety of fruit, look for it on a dwarfing rootstock first. If you can’t find one, check to see whether it’s available as a genetic dwarf.
Semi-dwarfing rootstocks dwarf the trees about 25 to 50 percent. Depending upon the type of fruit tree and variety, these may also be good choices for large containers.