Cherry trees, like many deciduous fruit trees, enter a period of dormancy during colder months. This natural winter rest is a necessary phase in their annual growth cycle, preparing them for robust spring growth and fruit production. Understanding this dormant state and providing appropriate care ensures the tree’s health and maximizes its fruiting potential.
The Winter Dormancy Cycle
As winter approaches, cherry trees transition into dormancy. Leaves drop, sap flow slows, and the tree hardens off, developing increased cold tolerance. This rest period, triggered by sustained cold temperatures, allows the tree to conserve energy and prepare for the next growing season.
The accumulation of “chilling hours”—specific periods of cold temperatures—is particularly important. Most cherry varieties require between 700 and 1,000 chilling hours to break dormancy uniformly and produce a good yield. Insufficient chilling can lead to delayed or uneven bud break, reducing flowering and fruit set.
Essential Pre-Winter Preparations
Preparing a cherry tree for winter begins in the fall, focusing on actions that bolster its resilience before freezing temperatures arrive. Thorough watering is particularly important in late autumn, ensuring the tree is well-hydrated before the ground freezes solid. This deep watering helps prevent desiccation, which can be a significant stressor during winter.
Applying a layer of organic mulch around the tree’s base provides insulation for the root system. A 2 to 4-inch layer of organic material, such as wood chips, shredded leaves, or straw, helps regulate soil temperature, retain moisture, and suppress weeds. Keep the mulch a few inches away from the trunk to prevent moisture buildup, which can lead to rot and create a haven for pests. Avoid excessive mulch thickness, as it can suffocate roots or attract rodents.
Fertilization should be avoided in late summer and fall. Applying nitrogen-rich fertilizers late in the season can stimulate new, tender growth that is highly susceptible to frost damage, undermining the tree’s hardening-off process. While major structural pruning is best reserved for late winter or early spring when the tree is fully dormant, any dead, diseased, or damaged branches can be removed in the fall. This light pruning helps improve tree health and reduces potential entry points for diseases during winter.
Winter Protection Strategies
Once winter arrives, active measures protect the cherry tree from environmental stressors and animal damage. Protecting the trunk from sunscald is particularly important, especially for young trees with thin bark. Sunscald occurs when the bark on the south or southwest side of the trunk heats up during sunny winter days and then rapidly freezes at night, causing cracks. This can be prevented by wrapping the trunk with a light-colored tree wrap made of paper or breathable fabric, or by painting the trunk white with diluted latex paint. Apply the wrap from the base of the tree up to the lowest branches.
Protection against rodent and animal damage is also important, as hungry animals can girdle young tree trunks by gnawing on the bark during winter. Install wire mesh or plastic tree guards around the base of the trunk, extending at least 18-24 inches high and burying the bottom few inches into the soil to prevent tunneling underneath. For areas with heavy snow, the guard should extend above the anticipated snow line. Gently shaking heavy snow loads from branches helps prevent breakage from excessive weight. Young trees in windy locations may benefit from staking to provide additional support against strong winter winds.
Addressing Winter Challenges
Cherry trees can encounter specific challenges during the winter months, which can be mitigated with proactive care. Frost crack, often linked to sunscald, manifests as longitudinal cracks in the bark, typically on the south or southwest side of the trunk. These cracks result from rapid temperature fluctuations, where the bark expands and contracts unevenly. The protective measures, such as tree wraps or white paint, help stabilize bark temperatures and significantly reduce the likelihood of frost crack.
Animal damage poses a persistent threat, with deer browsing on branches and rabbits or voles gnawing on bark near the ground. Tree guards and fencing offer physical barriers against these animals. Removing weeds and debris from around the tree’s base also discourages voles and mice, as these provide cover for them to operate undetected. While some diseases, like cankers, might appear more pronounced in winter due to tree stress or open wounds, proper sanitation and overall tree health are the best preventative measures. Avoiding late-season pruning of live wood helps minimize fresh wounds that could become entry points for pathogens.
Transitioning Out of Winter
As winter recedes and the threat of severe frost diminishes, attention shifts to assessing the cherry tree and preparing it for the growing season. Inspect the tree thoroughly for any signs of winter damage, such as broken branches, bark cracks, or evidence of animal gnawing. Any damaged branches should be pruned cleanly to prevent further issues.
When spring temperatures become consistently mild, typically after the last hard frost, remove tree wraps, guards, and any other temporary protections that were applied for winter. Leaving these in place too long can trap moisture, promote fungal growth, or girdle the trunk as the tree expands. Once the ground has thawed, provide the tree with its first deep watering of the spring. Observation of bud swell and the emergence of new foliage are positive indicators of successful winter survival and the tree’s readiness for the upcoming growing season.