The annual rituals of spring are upon us, and perhaps none is as intimidating as pruning your trees. Fruit trees, in particular, are a mystery to most of us. What should stay and what should go?
The decisions of what to cut and where are so confusing that many trees go unpruned.
Today we'll talk about apples and pears, the pome fruits. Next week we'll cover the plums, peaches, apricots and other stone fruits.
Solving the problem is Adrian Hinton, Utah State University Extension horticulturist in Utah County. His approach to pruning is tempered by many years of educational degrees, practical teaching and growing fruit in Arizona, New York, Washington and Utah County.
His advice is to start with the pome fruits. "Apples and pears are pruned first because they are the most hardy. They are pruned to one of two different systems. Older, standard size trees are often pruned to an open center configuration, while dwarf and semi-dwarf trees are pruned to a central leader."
Pruning fruit trees is much different from pruning ornamental trees, he said. Fruit trees need heavy annual pruning to stimulate new growth with many fruit buds. The wood must be in the sunlight for the fruit to size and ripen properly. Fruit also has to grow on healthy, vigorous shoots for best quality.
Hinton advises that you start with the obvious. First, clean up the tree. Remove all broken, dead or diseased wood whenever you find it, no matter what the season. Otherwise, most pruning is best done when the trees are dormant because the branches are bare and you can easily see what you need to remove.
"I like to tell people to walk around the tree and look at it from several angles as you prune. Take out a problem and then move around the tree and take out another and just keep removing the less desirable branches," he said. "Don't get too carried away. Never take out more than 20-30 percent of the wood in any one year because that will stimulate excessive growth of water sprouts in the tree."
Continue the cleanup at the base of the tree. "Remove all the suckers. These sprouts often come up from the base of the tree and often come from the rootstock. They will never have good fruit. Dig down to the roots and cut them off as close as possible to the rootstock. If you leave the base of the suckers, they will grow and you will have many more the following season. Continuing up the tree, look for branches that cross or rub each another. Remove any hanging branches or branches that grow parallel to each other."
After cleaning out the undesirable wood, focus on letting light into the tree. Water sprouts are the real culprits here. These shoots are long, vegetative sprouts that have no fruit buds. They grow straight into the air and shade out the interior of the tree so other fruit buds do not grow well.
One common mistake when pruning is trying to reduce the height of the tree without taking into account the growth responses. Cutting off the ends of the branches stimulates several buds to grow below the cut. These, in turn, make multiple sprouts that shade the inside of the tree and keep the fruit from growing well.
Cutting these sprouts off again multiplies the problem. Each cut stimulates several more shoots to grow and makes the problem even worse. The only way to solve the problem is to remove the sprouts clear to the base or cut them to side branches to direct their growth to make the tree spread out to collect more sunlight.
Although pruning in the dormant season makes it easier too see the branches, summer pruning is preferred to get rid of the recurring water spouts. They are not born 4 feet tall and an inch in diameter. Hinton reminds backyard orchardists that rubbing them off as they start to grow is much easier and is less stressful to the tree. Put on a pair of gloves and remove them regularly.
"The best way to train young dwarf or semi-dwarf apples is to start the day you plant them. If you prune them every year, you can keep them to the right size and shape and do not have to remove large limbs because potential problems are corrected when they are small," Hinton says.
The preferred method of training dwarf and semi-dwarf is to maintain a central leader. Start by selecting healthy well-grown trees. The biggest trees are not always the best. In most cases, it is best to start and train small trees. Many larger trees are already branching, but the branches are too high and are often in the wrong position. Correcting these problems usually requires removing the existing branches and starting again. Look for trees with straight trunks. If the trees are several years old and are not actively growing, they will never grow well and often are a runt tree.
Central leader trees are developed with tiers or whorls of branches with the longest and oldest at the base. The trees are developed into a conical or pyramidal shape so that the maximum number of fruits are exposed to full sunlight to help them grow well into high-quality produce.
Start the training by selecting four branches going out at the four points of the compass. Ideally the branches should be about the same diameter and separated by 4 to 6 inches on their position on the trunk.
If your tree has no side branches, cut the tree back to about 30 inches. This will stimulate side branches to train to form the first tier of branches. Do not forget to train or maintain a central leader because you need to develop additional tiers of branches.
The second tier is developed and trained 2 to 3 feet above the first. If possible, select these branches so they grow between the first tier. If the first branches face north, south, east and west, develop the next group so they face northeast, southeast, southwest and northwest. The third tier is developed another 2 to 3 feet above the first.
If you add up the height of the space between the tiers, the space between the branches, and the trunk, the tree will end up between 10 to 12 feet tall.
"A good guide for most gardeners is to maintain the trees at less than 12 feet because that is about as high as you can reach from a 6-foot ladder. Watch to make certain that you don't cut out the spurs. These smaller, more gnarled little sprouts are where the apples or pears are produced. They are essential because the clusters of five buds are inside," he said.
Pruning is essential because it lets the light in. The light is vital to produce both the color and the sugars in the fruit. Keep the fruit and the other growth in balance. A good rule of thumb is that it takes 28-30 leaves to produce one, high quality apple. Prune your trees right, and you will have an abundance of tasty fruit to enjoy this summer and to dry or can for the winter.
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