Q: I have a question about trimming our two dwarf grapefruit trees. We just removed all the fruit from them. We would like to trim up the bottoms (they both touch the ground, and when the fruit comes on and grows larger, they are very weighed down). There are some dead limbs in the middle also. Can we trim the citrus trees now before they start to bloom for the next batch of fruit?
A: Yes, you can prune your trees now. Dead limbs and sprouts (aka watersprouts or suckers) can be removed any time. Between February and April is best for pruning live branches. This allows the tree to leaf out and protect any limbs that may be exposed to sun. What is commonly called skirting or limbing up from the bottom should be done carefully to avoid taking off too much. The natural shape of these trees helps protect the bark from too much sun and resulting scalding damage that could occur. Removal of the low-hanging branches should only be to improve access to the soil surface, the irrigation system, or to the interior of the tree. Citrus wood is naturally strong and is not as likely to break under the stress of a large fruit load. Furthermore, citrus trees can produce fruit in all but the most shaded part of the tree, and need not be regularly pruned to allow light into the interior of the canopy. Even when the crop load is heavy, individual fruit size is large, so pruning to reduce the crop load and improve fruit size is not necessary except occasionally with tangerines. Finally, citrus fruit quality is typically just as good or better from a minimally pruned tree as compared with one that is heavily pruned. Lower canopy fruit often is of the best quality because it is not often affected by sunburn, scarring by windblown soil particles and by the movement of adjacent branches and twigs, or by bird predation.
Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed to firstname.lastname@example.org