Bay trees are grown all over the world for the leaves, which are used in cooking, massage therapy and for medicinal properties. Though fairly resistant to pests and disease, problems may nonetheless strike, causing the leaves to turn yellow on the bay laurel. You may be wondering why my bay laurel is turning yellow if you see yellowing of the bay laurel leaves.
Bay trees are evergreen shrubs that grow beautifully in either the garden or in containers. They make wonderful topiaries shaped as balls, pyramids, or “lollipops” and may even have braided or spirally trained stems. Laurus nobilis prefers to be grown in well-drained soil in a partially shaded or protected sun exposure. Grow bay outside in warm climates or indoors or greenhouse in cooler climates.
Why is My Bay Laurel Turning Yellow?
Leaves turn yellow on bay laurel for a number of reasons, resulting from an environmental condition, pest infestation or disease.
Root rot – A yellow bay laurel plant may be indicative of waterlogged roots or wet weather creating root rot, a fungal disease that does exactly what is says. This usually applies to container grown plants and symptoms also include leaf wilt and drooping as well as yellow leaves.
Avoid overwatering and standing water by providing adequate drainage. You may need to repot the bay in well draining, disease-free soil after removing any infected parts. An application of fungicide may be helpful as well.
Bay sucker pest – If your bay laurel has yellow leaves, another cause may be the bay sucker (aka: jumping plant lice), a common insect marauder of bay plants. These sap suckers are most active in late spring. Early signs of these pests are yellowing of the leaves followed by thickening of the leaf tissue, and finally brown leaves that drop.
Treatment for these pests is the removal of infested foliage on the yellow bay laurel plant. The damaged portions should be burned and then the bay should be treated with insecticidal soap focused on the underside of the leaves. You may need to treat more than one time.
Nutrient deficiency – Lastly, if your bay laurel has yellow leaves, the root of the problem may be either an iron or a nitrogen deficiency.
A deficiency in iron is also called iron chlorosis and is a major issue in the garden that is caused by several problems, most often overly alkaline soil or damaged roots. Too little iron decreases chlorophyll, resulting in yellow leaves beginning at the edges and moving inward while the veins remain green. Treatment is dependent upon the cause. If the soil is too wet or alkaline, mix organic matter, sulfur or peat moss into the soil to correct the pH and improve drainage.
A yellow bay laurel plant may be indicative of a nitrogen deficiency, which is caused by an imbalance in the pH of the soil. A uniform yellowing of the bay laurel leaves occurring in older, lower leaves first and moving upward is how a nitrogen deficiency can be diagnosed. Add a nitrate rich fertilizer to the soil, making sure to follow the directions lest you scorch the plant. A safer but slower option is to amend with decomposing organic matter to treat the nitrogen deficiency.