Pruning is a horticultural practice that involves the selective removal of parts of a plant to direct its growth and maximize performance. For mandarin trees, this process focuses on two primary goals: maintaining the tree’s health and increasing its capacity to produce a robust harvest of high-quality fruit. Since citrus trees are evergreen, they require less aggressive pruning than deciduous varieties. Careful cuts are necessary to ensure proper light penetration and air circulation throughout the canopy, resulting in a strong, balanced structure that supports heavy fruit loads without breakage.
Preparing for Pruning: Timing and Tools
The most effective time for pruning mandarin trees is in the late winter or early spring, just after the final fruit harvest but before the new flush of growth begins. Pruning at this time allows the tree to recover quickly as it enters its active growing season. Avoid pruning during peak flowering or fruiting periods, as this sacrifices the current season’s potential yield.
Heavy pruning should also be avoided during late fall or early winter, especially in areas prone to frost, because it encourages tender new growth easily damaged by cold temperatures. Essential tools include sharp hand pruners for small branches, loppers for branches up to about an inch and a half thick, and a pruning saw for anything larger. Sterilizing your tools with a bleach or alcohol solution before and after use prevents the transmission of disease between trees.
Pruning Young Mandarin Trees for Structure
The primary objective when pruning a young mandarin tree, typically within its first three to five years, is to establish a strong structural framework that will support future fruit production. This structural training dictates the overall shape of the tree, such as a modified central leader or an open vase shape. Select three to five well-spaced scaffold limbs that radiate outward from the trunk at wide angles. These branches will form the permanent foundation of the tree.
Any growth that emerges below the graft union, known as suckers, must be removed immediately, as this growth comes from the rootstock and will not produce desirable fruit. For a modified central leader shape, the main vertical shoot is kept but occasionally trimmed back to control height and encourage side branching. This technique helps create a strong, balanced canopy that allows sunlight to reach the inner parts of the tree.
Maintenance Pruning for Established Trees
Maintenance pruning is an annual activity focused on preserving the health of mature, fruit-bearing mandarin trees. Begin by removing any dead, diseased, or damaged wood, making cuts just outside the branch collar where the branch meets the trunk. This removes potential entry points for pests and pathogens and cleans up the canopy.
Next, thin the interior of the tree to improve air circulation and sunlight exposure, which is linked to better fruit quality and color. Removing crossing or rubbing branches prevents physical damage and allows light to penetrate the inner canopy, encouraging fruit production. You must also remove water sprouts, which are long, vigorous, vertical shoots that do not produce fruit and take energy away from the rest of the tree. When making cuts, always aim to cut back to a lateral branch or bud that is pointing in the direction you want new growth to travel.
Post-Pruning Care and Hygiene
Immediately following pruning, clean up all removed plant material from the ground around the tree. This debris can harbor pests or fungal spores, and removing it reduces the risk of disease spread. After pruning, the tree’s energy is directed toward healing the cuts and initiating new growth.
For most cuts on citrus, applying a wound sealant is discouraged, as these compounds can trap moisture and interfere with the tree’s natural healing process. The tree naturally seals the wound by forming callus tissue, a process called compartmentalization. The only exception is for very large cuts, where a sealant may be used to deter specific pests like the citrus borer. After pruning is complete, a balanced fertilization and proper watering schedule will support the tree through its recovery and new growth flush.