Winter care for a cherry tree directly influences the tree’s health and the abundance of the subsequent year’s harvest. During winter dormancy, the tree conserves energy and hardens its tissues against cold temperatures. Proper preparation in late fall and targeted protection throughout the coldest months safeguard the tree from desiccation, pests, and physical damage. Successfully navigating this phase ensures the cherry tree is poised for a robust bloom and fruit set when spring arrives.
Preparing the Tree for Dormancy
The transition into winter begins in late fall, signaling the tree to cease vegetative growth and prepare its wood for cold conditions. This preparation involves completely stopping nitrogen-rich fertilization by late summer or early fall. Continuing to apply nitrogen encourages soft, tender new growth that lacks lignification, making it highly susceptible to freeze damage and dieback.
The second late-fall task is ensuring the tree is adequately hydrated before the ground freezes solid. Cherry trees can suffer from winter desiccation, where the root system cannot replace moisture lost through the bark and buds in cold, dry air. A deep, slow watering around the tree’s drip line, applied just before consistent freezing temperatures are expected, provides a moisture reservoir that helps the plant survive until spring.
Sanitation of the area immediately surrounding the tree’s base is important. Fallen leaves, mummified fruit, and other organic debris can harbor fungal spores (like those causing cherry leaf spot) and house overwintering insect pupae (including the cherry fruit fly). Raking and removing this material breaks the life cycle of pests and diseases, reducing the inoculum load near the tree when it emerges from dormancy.
Protecting the Trunk and Roots from Winter Threats
Physical protection against environmental and biological threats is necessary, particularly for young cherry trees with thin bark. Sunscald is a common form of winter damage that occurs on the south or southwest side of the trunk. This injury happens when intense winter sun warms the dark bark, rousing the underlying cambial tissue from dormancy, followed by a rapid temperature plunge at night that freezes and kills the activated cells.
Cherry trees are vulnerable to sunscald due to their smooth, thin bark, which provides less insulation than other species. To prevent this, the trunk can be painted with diluted, white latex paint, or wrapped with a light-colored commercial tree guard. The white color reflects sunlight, maintaining a cooler temperature in the bark tissue throughout the day. The protective barrier should be applied in the fall and removed in the spring to prevent moisture and pest buildup.
The base of the trunk is a target for biological threats, such as rodents like mice, voles, and rabbits searching for food when other sources are buried under snow. These animals often girdle trees by chewing the bark entirely around the circumference, severing the phloem and xylem, which leads to the tree’s death. A cylinder of wire mesh, often hardware cloth, placed around the trunk and extending several inches into the soil or below the expected snow line, provides an effective physical deterrent.
Root protection is achieved through mulch, which helps insulate the soil and moderate temperature fluctuations. A layer of organic mulch, approximately three to four inches deep, prevents repeated freeze-thaw cycles that can heave the soil and damage shallow roots. The mulch must be applied in a donut shape, ensuring it does not touch the trunk directly, as this contact can retain excessive moisture and invite voles or fungal pathogens that cause crown rot.
Necessary Dormant Season Maintenance
Once the cherry tree is in dormancy, typically from mid-to-late winter, maintenance tasks can be performed to shape the tree and control future pest populations. Dormant pruning is best executed in late winter before the buds begin to swell and before sap flow begins. This timing is beneficial because the lack of leaves makes structural defects and dead or diseased wood highly visible, allowing for selective removal.
The primary goals of dormant pruning include removing crossing or rubbing branches, eliminating damaged wood, and opening the canopy for better light penetration and air circulation during the growing season. This practice maintains the tree’s health and shape, and prepares it to set fruit. Cuts should be clean and made just outside the branch collar to allow for proper wound healing.
Application of dormant horticultural oils or lime sulfur sprays is done during dormancy. These treatments smother overwintering insect eggs and larvae (such as scale, mites, and aphids) and control fungal diseases before they become active. The application must be performed when temperatures are above 40 degrees Fahrenheit and predicted to remain so for at least 24 hours to ensure the spray adheres and is effective without causing phytotoxicity.
After severe winter weather events, inspect all protective measures put in place during the fall. Check that wire mesh guards are secure against the base of the trunk and that tree wraps have not been damaged or loosened by wind or ice. Monitoring ensures that the physical barriers remain functional, providing continuous protection against winter threats.