The Bay Laurel (Laurus nobilis) is a fragrant evergreen shrub or small tree. Originating in the Mediterranean, this plant is accustomed to mild, temperate winters and struggles when exposed to prolonged freezing conditions. Protecting Bay Laurel from cold is necessary for gardeners in regions outside its native habitat, where winter temperatures frequently dip below freezing. Successful overwintering requires a combination of long-term cultural practices and immediate, active protection strategies to ensure the plant survives to produce new growth in the spring.
Understanding Bay Laurel Cold Tolerance
The Bay Laurel thrives outdoors year-round primarily within USDA Hardiness Zones 8 through 10. Foliage begins to sustain damage, appearing brown and desiccated, when temperatures drop to approximately 20°F to 23°F (-6°C to -5°C). This initial foliage injury is often a sign of cold burn and desiccation rather than total plant death.
The risk of permanent damage increases significantly when temperatures fall below 15°F (-9°C). At this lower point, the plant’s woody stems and root crown can suffer irreparable harm due to the freezing of water within the plant tissues. Because the roots of container-grown plants are more exposed and less insulated than those in the ground, they are more susceptible to root death. Understanding these specific temperature limits defines the level of protection needed when a cold snap is forecast.
Essential Pre-Winter Preparations
Preparing the Bay Laurel for winter begins well before the first frost. Gardeners should stop applying nitrogen-heavy fertilizers by late summer or early fall to prevent the development of soft, new growth that is highly susceptible to cold damage. The goal is to allow the existing wood to harden and mature before the cold weather arrives.
Proper water management during the fall helps build cold resistance. Ensuring adequate hydration before the ground freezes helps protect the roots from desiccation during winter winds. Improving drainage around in-ground plants or using a coarse potting mix for containers helps prevent root rot in cold, wet conditions. Container-grown plants should be moved to a sheltered position, such as against a south-facing wall or under a covered porch, well before the first hard frost.
Immediate Protection Strategies During Freezing
Physical protection is necessary to insulate the plant from dropping temperatures. For Bay Laurels growing in pots, the most effective strategy is to move them into a cool, sheltered location like an unheated garage or covered porch. This space should remain just above freezing, ideally between 35°F and 50°F (2°C to 10°C).
For plants established in the ground, insulating the root zone is the first priority to protect the root crown. A thick layer of organic mulch should be applied approximately six inches deep around the base of the plant. It is necessary to keep the mulch material a few inches away from the trunk itself to prevent moisture retention that could encourage disease or pest activity.
The shrub requires shielding from freezing air and harsh winds. Covering involves draping the entire plant with insulating materials like burlap or a commercial frost blanket. These coverings should extend all the way to the ground to trap residual heat radiating from the soil. Care must be taken to ensure that plastic sheeting, if used, does not directly touch the leaves, as condensation can freeze and cause direct tissue damage.
Constructing a temporary frame or cage around the plant allows the protective fabric to be suspended without crushing the branches. This air space between the foliage and the cover provides an additional layer of insulation. These covers should be removed promptly during the day if temperatures rise above freezing to prevent overheating and allow for proper air circulation.
Assessing and Treating Cold Damage
After the danger of freezing temperatures has passed, gardeners can assess the extent of any cold damage. Injury often includes leaves that appear brown, crispy, or blackened, and stems that may have turned dark and shriveled. Resist the urge to prune immediately after the cold event.
Wait until the plant begins its normal spring growth cycle. Determine which parts of the plant are still alive by scraping a small section of bark on a damaged stem. If the tissue underneath is bright green, the stem is still viable and should be left alone. Prune only the tissue that reveals brown or black coloration beneath the bark, cutting back to a point just above a healthy, outward-facing bud or to green wood. Even if all above-ground growth appears dead, the Bay Laurel often recovers slowly by sending up new shoots from the root crown.