Cherry tree survival through winter depends on a combination of factors, including the specific type of cherry, its age, and the environmental conditions of its planting site. Understanding these elements is important for ensuring your cherry tree remains healthy and productive.
Understanding Cherry Tree Hardiness
The ability of a cherry tree to withstand winter varies significantly by type. Sweet cherries (Prunus avium) generally thrive in USDA Hardiness Zones 5 to 9, preferring milder winters. Sour or tart cherries (Prunus cerasus) are more cold-tolerant, suited for Zones 4 to 8, with some varieties tolerating temperatures as low as -30°F to -40°F.
The USDA Hardiness Zone system indicates the average annual extreme minimum winter temperature for a location. Planting a cherry tree suited to your specific zone is important for its winter survival and overall health. While some cherry trees tolerate temperatures down to -30°F to -40°F, prolonged exposure to extreme cold, especially below -20°F, can cause damage.
A cherry tree’s age also influences its winter resilience. Young, newly planted trees are more susceptible to winter injury than mature ones. Their developing root systems are less able to cope with frozen soil and temperature fluctuations, making their protection a greater concern.
Site selection plays a significant role in a cherry tree’s hardiness. Planting cherry trees in a location with full sun, good air circulation, and well-drained soil helps them develop robustly. Protection from strong winter winds can also prevent damage to bark and branches.
Preparing Cherry Trees for Winter
Proactive steps taken in the fall can significantly enhance a cherry tree’s resilience against winter conditions. Adequate fall watering, especially before the ground freezes, ensures the tree is well-hydrated throughout its dormant period. Deep watering allows moisture to penetrate the root zone, providing a reserve when water uptake from frozen soil is limited.
Applying a 3-4 inch layer of organic mulch, such as straw or wood chips, around the tree’s base insulates roots, retains soil moisture, and protects against freezing. Apply mulch in late fall after several frosts, keeping it a few inches away from the trunk to prevent rodent activity and moisture buildup that could lead to rot.
Avoid late-season pruning after mid-summer. Pruning stimulates new growth, which can be susceptible to cold damage if it doesn’t harden off before winter. While dead or diseased branches can be removed anytime, significant structural pruning is best reserved for late winter or early spring when the tree is dormant.
Fertilization practices in the fall also impact winter hardiness. Avoid nitrogen-rich fertilizers late in the growing season, as nitrogen promotes tender growth that may not adequately harden off. Overall tree health going into winter is a contributing factor to its ability to survive. A tree free from pests and diseases, with sufficient nutrient reserves and proper hydration, is better equipped to handle the stresses of cold temperatures and adverse weather.
Common Winter Challenges and Protection
Cherry trees face several specific winter challenges, requiring targeted protective measures. Sunscald is a common issue, occurring when rapid temperature fluctuations cause damage to the bark, particularly on the south or southwest side of the trunk. Intense winter sunlight warms the bark during the day, followed by freezing temperatures at night, leading to cracks. To prevent sunscald, tree wraps made of paper or burlap can be applied to the trunk, or the trunk can be painted with a diluted white latex paint to reflect sunlight.
Frost cracks, which are vertical splits in the trunk, are also related to temperature changes and can be exacerbated by existing weaknesses in the bark. The expansion and contraction of water within the tree’s tissues during freeze-thaw cycles contribute to these cracks. Protective measures similar to those for sunscald, such as trunk wraps, can help mitigate the risk of frost cracks by stabilizing bark temperatures.
Rodents, including mice, voles, and rabbits, pose a threat to cherry trees during winter, especially under snow cover. These animals can girdle tree trunks by chewing on the bark, which can severely damage or even kill the tree. Protecting the trunk with tree guards made of wire mesh or hardware cloth can create a physical barrier against these pests. These guards should extend above the anticipated snow line.
Heavy snow and ice accumulation can lead to branch breakage, particularly on younger or weaker limbs. Excessive weight from frozen precipitation can cause structural damage. Gently removing snow from branches with a broom can help alleviate this stress, but it is important to avoid aggressive methods that could cause further breakage.
Assessing and Recovering from Winter Damage
Once winter has passed, assess your cherry tree for signs of damage. Visual cues of winter injury include dead buds, blackened or discolored branches, and bark splits. The full extent of damage may not be immediately apparent, requiring patience to observe how the tree leafs out in spring.
Pruning away dead or severely damaged wood is an important recovery step. This should be done in late winter or early spring before new growth begins. When pruning, make clean cuts into healthy wood to remove injured sections, which helps prevent disease and encourages new growth. Avoid removing too much live wood at once, as this can stress the tree further.
Post-winter care involves supporting the tree’s natural healing processes. Provide adequate water as the weather warms, ensuring the soil remains consistently moist but not waterlogged. Avoiding excessive fertilization in early spring is also recommended, as the tree needs to prioritize healing before putting energy into vigorous new growth.
Some trees may take time to show signs of recovery, and patience is often required. Even if a tree appears significantly damaged, it may surprise you with new growth from the roots or lower trunk. Continued observation and appropriate care can help a cherry tree bounce back from winter stress.