Sour cherry trees (Prunus cerasus) benefit significantly from regular pruning to maintain health and maximize the fruit harvest. Pruning manages the tree’s structure to encourage strong, productive growth, ensuring it can support a heavy fruit load. Selectively removing parts of the canopy improves air circulation and sunlight penetration, which are linked to fruit quality and disease prevention.
Essential Tools and Timing
The best time to prune sour cherries is late winter or early spring, during the tree’s dormant season, after the threat of the harshest cold has passed. Pruning during this window minimizes sap bleeding and stimulates vigorous new growth when the tree emerges from dormancy. Pruning while the tree is leafless provides a clear view of the structure, allowing for more accurate removal of wood.
Specialized tools are necessary to make clean cuts that heal quickly. Use bypass hand pruners for branches up to a half-inch thick, long-handled loppers for thicker limbs, and a curved pruning saw for branches exceeding one and a half inches. Before starting, sterilize all cutting surfaces with a 10% bleach mixture or rubbing alcohol to prevent the transfer of fungal or bacterial diseases.
Establishing the Structural Goal
Sour cherries naturally tend toward an open-center structure, which influences the pruning approach. The primary goal is to train the tree into a manageable shape that allows maximum sunlight to reach the inner canopy and lower branches. Tart cherries produce fruit on short shoots called spurs and on one-year-old wood, making sunlight exposure important for renewing these fruiting areas.
A common approach is the open-center or vase shape, where the central leader is removed early to encourage three to five strong scaffold branches. This structure creates an open bowl in the tree’s center, ensuring light reaches the lower parts of the tree. A thinning cut removes an entire branch back to its point of origin, while a heading cut shortens a branch to an outward-facing bud. Thinning cuts are often preferred in sour cherry pruning to maintain the open structure.
Step-by-Step Cutting Techniques
Start by eliminating the “three D’s”: dead, diseased, or damaged branches, cutting them back to healthy wood or the main trunk. This minimizes the risk of pathogens spreading and directs the tree’s energy away from compromised areas.
Next, remove suckers (shoots arising from the roots or base of the trunk) and water sprouts (fast-growing, vertical shoots in the canopy). These non-fruiting growths steal energy from productive parts of the tree and should be cut flush with the wood from which they originate. Air circulation is improved by thinning out branches that cross over or rub against one another, as rubbing creates wounds that are entry points for disease.
Structural cuts are then performed to maintain the desired open shape and control the tree’s size. Selectively remove older, less productive branches to encourage new, one-year-old wood, where a significant portion of the fruit will be borne. All cuts must be made just outside the branch collar, the slightly swollen ring of tissue where the branch meets the trunk. Cutting flush or leaving a stub hinders the tree’s natural compartmentalization process, which seals off the wound.
Post-Pruning Care and Sanitation
Once pruning is complete, immediate attention must turn to cleaning up the workspace and sanitizing the tools. All removed branches, especially those that were diseased, should be promptly collected and disposed of away from the orchard area to prevent disease spores or pests from reinfecting the tree.
Wound dressings or pruning paints are generally not recommended for sour cherries. Research suggests they often trap moisture and slow the tree’s natural healing process. The tree’s built-in defense mechanism, known as compartmentalization, is most effective when the cut is clean and left exposed to the air. Proper watering and a balanced fertilizer application, if needed, will help support the tree’s recovery and new growth in the upcoming season.