Blueberry Plants & Yellow Leaves

Soil pH Requirements

• Blueberry bushes need a low soil pH to succeed. If the soil pH is too high, the plant will suffer from yellow leaves, smaller than normal leaf sizes, stunted growth and poor fruit production. The blueberry bush requires a soil pH range of 4.0 to 5.5. When the pH level is above 5.5, the plant's first symptom is yellowing of the foliage. Always check the soil pH prior to planting a blueberry bush. Adding sulfur, peat moss and leaf mulch six months prior to planting the blueberry bush will help reduce the soil's pH and create a more acidic planting site.

Nutritional Deficiences

• Nitrogen, sulfur and iron deficiencies can cause the leaves of the blueberry plant to yellow. If the soil pH is too high, the blueberry plant will not have the ability to absorb enough iron from the soil. Without adequate iron, the blueberry plant will suffer reduced growth and eventually die. The new leaves of a blueberry plant suffering from an iron deficiency will appear yellow in the green veins. Nitrogen and sulfur deficiencies cause the entire leaf to turn yellow. Older leaves turn yellow first when insufficient nitrogen is present in the soil and new development turns yellow with a sulfur deficiency. The plant will respond well to applications of nitrogen and sulfur. Foliar sprays of iron can also help.

Sunlight and Water

• The blueberry plant has extremely precise planting requirements. If the plant receives too much sunlight, it will suffer yellowing leaves. Yellow foliage that appears only on the south or west side of the plant indicates that the plant suffers from overexposure to sunlight. Transplant the blueberry bush if it cannot be shaded from the sunlight. Blueberry plants subjected to periods of drought will also suffer yellow leaves. If the plant does not receive sufficient water, the leaves will begin to fall from the shrub.

Diseases and Fungal Infections

• The fungus Botryosphaeria dothidea causes a condition known as stem blight to appear on the blueberry. The plant's foliage becomes yellow, red and brown. The wood of the stock will also show discoloration if split open. Avoid wounding the blueberry plant during cultivation to prevent the disorder. Prune away infected areas and discard. The fungal infection Botrytis blight (Botrytis cinerea) causes yellow leaves, defoliation and yield loss. Treat using fungicides. Blueberry leaf mottle appears to only affect Rubel and Jersey cultivars. The foliage appears mottled. Promptly remove and destroy all infected stems. If the disease continues, remove the infected bushes and replace with disease-resistant cultivars. The Mosaic virus causes severe yellowing and mottling of the blueberry plant's leaves. It occurs predominately on Rubel, Pioneer, Stanley, Concord and Cabot cultivars. Prune off the infected branches and destroy them.