Why Are the Needles on My Evergreen Bush Turning Yellow?

Poor Irrigation

• The excess or lack of water in the root zone causes damage to roots thereby reducing oxygen, nutrient and water flow in the plant. Poorly growing roots also make the plant prone to infection from numerous fungi. Damage is indicated by yellowing and discolored foliage.

Pathogenic Disorders

• Evergreens are susceptible to a variety of pathogenic disorders that lead to yellowing foliage. Common diseases include shoot blights, needle casts and cankers. Diseases that cause yellowing include cyclaneusma needle cast of pine caused by Cyclaneusma minus, lophodermium needle cast and rhizosphaera needle cast caused by Rhizosphaera kalkhoffii.

Pest Infestation

• Evergreen shrubs are prone to infestation from aphids, small sap-sucking, pear-shaped insects that damage the plant with their feeding. Infested foliage is distorted, yellow and curled. Shoots are stunted. As they feed, the pests secrete a sticky honeydewlike substance that leads to the development of black, sooty mold fungus on infested plant areas.