Cherry Laurel (Prunus laurocerasus) is a widely popular broadleaf evergreen shrub known for its dense, glossy foliage, making it a favored choice for hedges and screens in many temperate regions. This year-round greenery provides valuable structure in the garden, but its evergreen nature is precisely what introduces sensitivity to extreme cold. For gardeners in climates approaching the lower limits of its tolerance, understanding how much cold the plant can withstand is important for its long-term health.
Understanding the Hardiness Limits
The general hardiness range for Cherry Laurel typically falls within USDA Zones 6 through 9, but the precise temperature limit varies considerably between specific cultivars. Most common English Laurel varieties are reliably hardy down to approximately 0°F to -5°F (about -18°C to -20°C). Cultivars developed for increased cold tolerance, such as ‘Schipkaensis’ (Skip Laurel) or ‘Otto Luyken’, can often survive in Zone 5, handling temperatures potentially as low as -10°F to -20°F (about -23°C to -29°C) with minimal damage.
The duration and speed of the temperature drop are often more significant than the absolute minimum temperature reached. A sudden, acute freeze in early winter, before the plant has fully acclimated, causes more widespread damage than a prolonged cold snap in mid-winter that the plant was prepared for. When temperatures linger near or below the lower threshold for an extended period, the risk of deep tissue and root damage increases substantially, regardless of the cultivar’s rating.
The Science of Cold Tolerance
The ability of a Cherry Laurel to withstand cold hinges on a biological process called “hardening off,” which occurs naturally as autumn progresses. Decreasing day length and gradually falling temperatures trigger the plant to slow growth and move water out of its cells into the intercellular spaces. This deliberate dehydration concentrates the remaining solutes, like sugars, in the cell fluid, effectively lowering its freezing point, functioning as a natural antifreeze.
Broadleaf evergreens face a specific challenge because they retain their large leaves throughout the winter, which allows for continuous water loss through transpiration. If the ground is frozen solid, the roots cannot absorb replacement water, leading to a moisture deficit in the leaves. This desiccation, often called winter burn, results from a lack of water rather than direct freezing and is a significant cause of damage even when the air temperature itself is within a tolerable range.
Identifying Freeze Injury
The most common sign of cold damage is “winter burn,” which manifests as bronzed, scorched, or entirely brown leaves, typically concentrated on the side of the plant facing prevailing winter winds or bright sun. This leaf scorching is a visual indicator that the foliage has dehydrated beyond recovery because the frozen soil prevented water uptake. While unsightly, damage confined to the leaves is often cosmetic, and the plant will usually shed the damaged foliage and produce new growth in the spring.
More severe cold injury involves damage to the stems and buds, which can lead to dieback. Stem splitting or cracking, sometimes forming small cankers, indicates that the bark and underlying cambium layer have been compromised by ice formation within the tissues. If the terminal buds—the small growth points at the end of a branch—are brown or black and do not swell in the spring, the stem has died back and will require pruning to a point of healthy, green wood.
Strategies for Winter Protection
Protecting Cherry Laurel from cold damage begins with thoughtful site selection, ideally choosing a spot sheltered from strong northern or western winter winds, which accelerate desiccation. Planting near a structure or in an area that receives afternoon shade in the winter can reduce the leaf temperature fluctuations that contribute to water loss. Proactive care in the late autumn is much more effective than reactive measures once a hard freeze hits.
Identifying Freeze Injury
The most common sign of cold damage is “winter burn,” which manifests as bronzed, scorched, or entirely brown leaves, typically concentrated on the side of the plant facing prevailing winter winds or bright sun. This leaf scorching indicates the foliage has dehydrated beyond recovery because the frozen soil prevented water uptake. Damage confined to the leaves is often cosmetic, and the plant usually sheds the damaged foliage and produces new growth in the spring.
More severe cold injury involves damage to the stems and buds, which can lead to dieback. Stem splitting or cracking, sometimes forming small cankers, indicates that the bark and underlying cambium layer have been compromised by ice formation within the tissues. If the terminal buds—the small growth points at the end of a branch—are brown or black and do not swell in the spring, the stem has died back and will require pruning to a point of healthy, green wood.
Ensuring the root system is fully hydrated before the ground freezes is the most effective preventative measure against winter burn. Provide a deep, thorough watering late in the fall, especially if the season has been dry, to saturate the soil and maximize water reserves. A final deep soaking just before the first hard freeze is beneficial, as broadleaf evergreens lose moisture throughout the winter.
A layer of organic mulch, such as wood chips or shredded bark, spread 2 to 3 inches deep around the base of the shrub, helps insulate the soil and maintain consistent moisture by slowing the rate of freezing and thawing. The mulch should be pulled back a few inches from the main stem to prevent moisture from accumulating directly against the bark, which could lead to rot.
For younger or more exposed plants, physical barriers offer protection against wind and sun scald. Temporary screens made of burlap or specialized windbreak fabric can be erected on the windward side to slow air movement and shade the foliage from intense winter sun. These barriers should be placed a short distance from the plant to allow for air circulation and removed promptly once harsh weather has passed to prevent disease development.
Anti-desiccant sprays, which are waxy emulsions applied to the foliage in late autumn, form a thin film that helps reduce the amount of water lost through transpiration on sunny or windy winter days. Using these sprays is especially helpful for newly planted shrubs or those in exposed locations where wind desiccation is a known problem.