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  • Articles Index : Citrus and Other Fruits



    11. To Prune, or Not to Prune - Citrus That is - Top

    When most of us think about pruning fruit trees, we envision those peaches, apples and plums we used to grow before moving to Tucson. The pruning on those stone and pome fruits was done yearly and rather severely. It was the only way to ensure the production of abundant and high-quality fruit. But now, were growing citrus here in Tucson, and citrus is a fruit of a different color all-together.

    Citrus trees, whether orange, tangerine, grapefruit, lemon or lime are really large, over-grown shrubs; it just happens they produce delicious fruits. They don't grow as, nor should they be pruned like other fruit trees, trees, or for that matter even shrubs. A little known fact about citrus is: the more green leaves there are, the more abundant and delicious the fruit will be. Another interesting bit of information revealed to me by a seasoned orange grove manager is that the sweetest fruit are always located on the southwest side of the tree.

    Now as to pruning citrus; given that more leaves equates to more and better fruit, then prune only if you must and only using the proper techniques.

    One of the first things people want to do with their citrus tree is to prune off the lower limbs. In an effort to make citrus more tree-like, it's acceptable to trim up some of the lower branches. However, those branches which shade the base of the trunk from exposure to direct sunlight should not be removed. The bark on trunk, and also branches of citrus sunburn very easily when exposed to direct sunlight. This sunburning of the wood will cause the bark and underlying cambium layer, which transports water and nutrients, to die!

    It's not harmful if branches hang all the way to the ground, although it might make it a little more difficult to fertilize under the tree. Disease will not develop if the ends of lower branches touch the ground. If you do decide to remove some of the lower limbs, cut them back to the trunk. Don't just cut the outer portions. Chances are the remaining inner branch sections will not produce fruit anyway.

    Pruning cuts made on citrus trees, or for that matter trees in general, should not be treated with pruning paint or wound dressing. These products only inhibit the tree's natural healing process. Most contain tar or asphalt compounds that can actually harm the tree.

    From time to time it may be necessary to prune errant branches; those growing into or too close to your house, patio or walkways. Try to remove as few branches as possible. If a large limb must be pruned off, don't do it now! Wait till mid-November when sun intensity has decreased and when pruning will not promote soft fall growth, more susceptible to freezing injury. If a large limb is removed too late in the spring, new growth will not develop fast enough to shade exposed wood and sunburn will result.

    If a large branch or branches must be removed during the spring and summer months, immediately whitewash any branches or trunk portion exposed to direct sunlight. Use a solution of one part white latex paint to nine parts water for a whitewash to be applied to exposed bark. The whitewash will reflect sunlight and prevent the bark from scorching.

    Unlike lower branches, when pruning side or top branches, remove only the part of the branch causing the problem. Prune it back to a branch fork, side branch or stem. Don't leave stubs that can cause a rot to move down into heathy wood. Also, don't use pruning paint.

    Fruit on citrus can also sunburn. When it does, a rounded, buff-colored patch develops on the side of the fruit most exposed to direct sunlight. Fruit burn can occur on any side of the tree, but is usually on the south and west facing portions. The types of citrus fruit most susceptible to sunburn are tangelos, tangerines and oranges. Usually, fruit burn does not effect the quality of the fruit, only the appearance of the outer rind. The only way to prevent it is to cover the tree with shade cloth from June through August.

    Finally, keep in mind that citrus, allowed to grow as large shrubs are healthiest and will produce the most and best quality fruit. So, if your really into prune fruit trees, consider growing yourself a peach or apple tree.

    Written by John Begeman, College of Agriculture and Life Sciences, the University of Arizona,
    520-626-5161. - Updated: August 15, 2004

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