At the elementary school I attended in Tempe, Arizona, I was taught the Five C’s of Arizona. They are: Copper, Cattle, Cotton, Citrus and Climate. For this article, I will focus on the fourth C on this list. Arizona’s climate is perfect for growing citrus trees, but not all Arizonans know how to care for them. The biggest mistakes commonly made involve how and when to prune citrus trees. Many people are concerned about WHEN they should prune their citrus trees, although that is not the most important question involved. For some, the answer might be: NEVER! Perhaps a more appropriate question is: why should No prune my citrus trees?
Why NOT prune citrus trees
When a Valley resident asked The Arizona Republic’s garden expert when she should prune her citrus trees, this was part of her response: “Homeowners like to prune their citrus trees to improve the appearance. Did you know that citrus trees are actually shrubs and their branches grow naturally low to the ground? That’s Mother Nature’s way of protecting the fruit and bark…” Those who have driven through the old growth forests that still exist in parts of East Mesa they can understand this idea of citrus trees as overgrown bushes. The popular misconception that citrus trees should be pruned the same way as any other type of tree means shorter life for many citrus trees in the Phoenix area. That’s why I’d like readers to ask why want to cut them out before wondering about when to prune your citrus trees. Whether the goal is to optimize citrus production or simply to have your citrus trees add aesthetically to your garden, you need to keep their overall health in mind when pruning them.
How to Prune Citrus Trees
Even if done during the most optimal time of year, any pruning should be minimal. As Dave Owens, also known as ‘The Garden Guy,’ states, “Citrus trees like to be left unpruned. The more foliage and dead wood on the tree, the more sun protection the trunk will get.” John Begeman, another Arizona gardening expert, notes that “more leaves equals more and better fruit,” and also recommends pruning “only if necessary and only with proper techniques.” As described in a 1987 article by Lowell F. True, some trimming may be necessary. Although it’s best to leave a ‘skirt’ (branches that almost touch the ground), it’s okay to cut it back just enough to make watering and fertilizing easier. Wandering branches can also be trimmed, especially if they rub against other branches. As for the outer foliage, the silhouette of the tree, can be “shaped” for aesthetic purposes, as long as great care is taken to avoid exposing too much bark of the tree to sunlight. There is only one type of pruning that can and should be done regardless of the time of year, especially if you are maintaining citrus trees for their fruit: the removal of sucker growth. These suckers are also called ‘water shoots’ and will sprout from the trunk or even the roots of the tree. A layman may feel that this is necessary out of intuition or a desire to make the tree look good, but there is in fact a good reason behind it. True says: “Be sure to remove all suckers that arise below the bud union [which is the site of grafting]. They are of the rootstock variety and will not bear edible fruit. When allowed to develop, they will take over the tops, causing the aforementioned citrus variety to revert to being an unwanted variety.” Spring growth has begun, so you can be sure of the extent of the damage.
When to Prune Citrus Trees in Arizona
The best time of year to prune citrus trees is in the spring. If you prune between mid-March and early May, the trees are less likely to be damaged by extreme temperatures. Citrus ripens in late fall, from about November through February for most varieties. Minimal pruning during this harvest time is also acceptable. During the winter there is danger of frost, and during the summer the problem is the opposite. Citrus trees are very sensitive to sun damage, especially during the hottest months of the year and during the hottest hours of the day. If the tree does not receive shade during the afternoon, any bare trunks or branches should be wrapped or painted (whitewashed) to protect them from the sun. The tree is most vulnerable where it receives direct sunlight in the afternoon: the southwest exposure. That’s why it’s so important not to over-prune citrus trees: branches exposed to direct sun will burn, and full trunk exposure can kill the tree entirely.
In conclusion, I would like to re-emphasize that knowing when to prune citrus trees is not as important as knowing how to prune them. The number one rule for knowing when to prune citrus trees is sun. The number one rule for how to prune citrus trees is minimalism. Remember, they are really just big bushes.
SOURCES (in order of citation within the article): the republic of arizona: Southwest Gardens, Diana Balazs. The Garden Guy: “Citrus Trees” by Dave Owens. Arid-Southwest Gardening Information: John Bergman [http://www.ag.arizona.edu/gardening/news/articles/3.30.html], University of Arizona College of Agriculture and Life Sciences. “To prune or not to prune: citrus, that is.” Lowell F. True, University of Arizona College of Agriculture “Citrus in the Home and Garden”