Gardening Articles: Edibles :: Fruit & Nut Trees
Fruit Trees in Containers (page 3 of 4)
by William Ross
Hedge Clipping and Root Pruning
Pruning controls a tree's size and shape, maximizes fruit production, and maintains tree health. Hedge clipping and "cleaning out the inside" are the minimum treatments.
To prune, remove all foliage from the inside branches of the tree so that most of the foliage grows on the outside. Pay attention to the fruit location. On many citrus plants, the fruits are on the tips of small branches, and many of these fruits are always left, even after the most severe pruning.
During the first few years, you may prune a newly transplanted tree, but allow the tree to increase in size several inches a year. As it approaches mature size, prune to limit its increases to up to 1 inch per year. Most container plants eventually reach an optimum size for a specific container size. Fruit trees, especially citrus, can live more than 75 years, so annual repotting is the best way to maintain the health and vigor of both plant and soil.
In the spring, repot the plants before putting them outdoors for the summer. Remove about an inch of the rootball, and comb the root tangles. Prune a similar amount of foliage at the same time. Additional summer pruning is necessary to limit the tree's size.
The best pruning job I've ever seen was done by a herd of cows on a wild apple tree. Every spring, the cows grazed the tree down to a stub; they ate most of the new growth from summer until fall, when they would leave it alone. This tree was a perfect sphere of foliage about 5 feet tall and about 60 years old. The cows had created a perfect bonsai specimen.
As the art of bonsai demonstrates, you can limit almost any tree to any size by careful pruning. I have a 1-foot-tall 'Ponderosa' lemon in a 1-gallon pot that produces 3 pounds of fruit a year. Of course, the smaller the pot, the more attention you must pay to watering, fertilizing, root and foliage pruning, and repotting.
Deciduous trees, such as apples and cherries, require a period of temperatures between 32o to 40oF. in order to fruit properly the following year. Gardeners in mild-winter regions should look for fruit trees adapted to fewer chill hours.
If you're not in a mild-winter zone, move your fruit trees indoors in winter or protect them outdoors. After their leaves drop in the fall, deciduous trees should be kept moist and moved to an unheated garage. You can also keep them insulated outdoors to prevent freezing and thawing of the roots. To insulate your outdoor trees, tie up the branches, create a wire-mesh cylinder (around the tree and container) 1 foot wider than the tree canopy, fill the cylinder with leaves or straw, wrap the cylinder with burlap, and cover the top with plastic to shed water.
Citrus and tropical trees should be moved to a heated greenhouse or solarium before the first frost to overwinter indoors. Some citrus and tropicals m need supplemental light and heat in winter for best fruiting. However, excessively hot and dry conditions can cause citrus to drop fruit. In that case, you should mist the foliage with tepid water. Citrus will often have flowers and fruit at different stages on the same tree, and ripe fruit can be left on the tree for weeks.