Southern California's subtropical climate makes it the perfect growing region for oranges, grapefruits, lemons, limes, tangerines and other citrus fruits. Citrus ripens during winter months and waiting until the season is over to trim your citrus tree ensures you get the largest crop. Unlike other fruit trees, citrus trees don't need pruning for shaping and benefit from very little pruning. They are susceptible to disease and wounds, so prune lightly and predominantly to remove unhealthy growth from your citrus tree.
Harvest your citrus fruit before you trim the tree, sometime in late winter to early spring. When you harvest depends on the type of citrus you grow. In Southern California, mandarins ripen primarily from October to March and Meyer lemons ripen from November to March. Pick all fruit before you attempt to prune.
Combine one part bleach with 10 parts water in a bucket. Place your pruning tools in this bucket.
Check over the branches of your California citrus tree for signs of dead, damaged or diseased growth. Dead branches will not move in the wind and will feel light or hollow. Damaged and diseased growth may have wounds, cuts, discoloration or other blemishes. You can identify it clearly as looking different from healthy growth.
Cut away any unhealthy wood using your tools. Anvil pruners cut wood up to 3/4-inch in diameter while lopping shears work on larger branches. In between each cut of the wood, dip your pruning tools back into the bleach solution to disinfect it.
Clip off suckers from the trunk of the tree. Suckers do not bear fruit and sap energy from the tree. They grow out of the trunk and from the Y-intersections between branches.
Thin additional growth from heavy areas to allow light penetration into the canopy. This helps fruit to ripen. Identify weak limbs or old limbs and trim them off at their base with your pruning equipment.