Bay trees (Laurus nobilis) are popular garden plants, valued for their aromatic leaves used in cooking and their ornamental appeal. As colder months approach, gardeners often wonder about their winter behavior and whether they shed leaves. Understanding how these plants adapt to seasonal changes is important for their health.
Bay Trees: An Evergreen Nature
Bay trees are evergreen, retaining their foliage throughout the year. This allows them to continuously photosynthesize, even during cooler winter days, though at a reduced rate. Unlike deciduous trees that shed all their leaves, bay trees maintain a consistent green appearance and year-round visual interest.
While bay trees do not undergo complete defoliation, a natural, gradual shedding of older leaves occurs. These older leaves may turn yellow before falling off, which is a normal part of the plant’s life cycle as it produces new growth. This process is distinct from the mass leaf drop of deciduous species and is not a concern if new foliage emerges.
Understanding Leaf Drop in Bay Trees
While some leaf shedding is natural, excessive or sudden leaf drop in bay trees indicates underlying issues. This often points to environmental stress rather than a natural process. Problematic leaf loss can manifest as leaves turning yellow or brown before falling.
Environmental factors are frequent culprits for unusual leaf drop. Fluctuations in temperature, especially cold snaps or temperatures below -5°C (23°F), can damage leaves and lead to shedding. Improper watering, including overwatering or insufficient watering, can also cause leaves to yellow or brown and drop. Lack of adequate light, particularly for potted plants moved indoors, can weaken the tree and contribute to leaf loss. Pest infestations like scale insects or spider mites, and diseases such as root rot or leaf spot, can also compromise the tree’s health and result in significant leaf drop.
Winter Care for Bay Trees
Bay trees retain their leaves through winter, so their care during colder months focuses on protection. For container-grown bay trees, protecting them from frost and extreme cold is important, as their roots are more exposed. Moving potted bay trees to a sheltered, unheated location like a garage or greenhouse when temperatures drop below freezing, especially around -5°C (23°F), can prevent damage. If moving is not feasible, wrapping the pot with bubble wrap or horticultural fleece insulates the roots, and covering the foliage with fleece protects against harsh winds and frost.
Watering techniques require adjustment during winter. Bay trees do not like waterlogged conditions, especially in colder temperatures, but they still need some moisture. Avoid overwatering, which can lead to root rot, but ensure the soil does not dry out completely, particularly for containerized plants. Allowing the top inch or two (2.5-5 cm) of soil to dry before watering is a good practice. For trees in the ground, a layer of winter mulch around the base insulates roots and retains soil moisture.