Why Does My Rosemary Look Unhealthy?

Are the older leaves rotted?

Are the leaves covered with white powder?

Are the leaves yellowing, wilting and, dying?

Are there any small translucent spots on leaves, spots later turn black?

Do leaves have water-soaked spots on them?

Are the leaves distorted, yellowed, and stippled?

Are the leaves yellow and the plant looks weakened?

Do the leaves and stems have white, cottony clusters on them?

Are the leaves covered with small bumps?

Botrytis blight fungal infection rots the older leaves in the center of a rosemary plant. You can prevent Botrytis blight disease by planting flowers in areas with good air circulation. Water plants sparsely. Severely infected plants should be removed. Spray weekly with a copper fungicide until the disease is under control.

White, powdery patches on the leaves are caused by a fungal disease Powdery mildew. Powdery mildew usually appears in damp places. Encourage good air circulation around the affected plants by thining them and any surrounding plants. Water plants from bellow to keep foliage dry. Any affected leaves should be cut off and removed.

Yellow leaves that wilt and die usually indicate Root rot. Poorly drained, overly wet soil promotes rot so choose well-drained sites and add organic matter to improve drainage. Remove and destroy infected plants. Solarize the soil before replanting.

Bacterial leaf spot causes circular translucent spots scattered over the leaf surface. These spots turn brownish-black and may spread to form large patches of dead tissue. To prevent the spread of this disease, avoid working around wet plants. Remove and destroy affected parts. Spray Bordeaux mix on remaining plants.

Water-soaked spots on leaves are caused by bacterial blight. The copper spray will help in reducing the spread of the disease. If there are no new pods on the plant, you should remove the diseased plants.

Leaves stippled with yellow are caused by mites. These tiny, spider-like pests feed by sucking sap from the underside of the plants leaves causing yellow flecking on the upper leaf surfaces. You can control spider mites by spraying plants thoroughly with water 2-3 times a day for several days. For severe infestations, spray plants with insecticidal soap.

Yellow leaves and stunted look are caused by whiteflies. These tiny, mothlike flies and their larvae feed by sucking plant juices. Whiteflies secrete honeydew, a sugary substance that makes leaves sticky to the touch. Control whiteflies by eliminating garden weeds and by introducing green lacewings in the garden. Spray infested plants with insecticidal soap every 3 days for 2 weeks.

White, cottony clusters on leaves and stems are caused by mealybugs. These tiny insects are covered with a fluffy white coating. They feed by sucking plants sap. They produce sticky substance honeydew which makes leaves sticky. You can control them by washing them off the plant with water spray. Insecticidal soap should be used with severe infestations.

Leaves covered by small bumps are caused by scales. These tiny, shelled insects often feed on the undersides of the leaves, causing an unhealthy appearance with yellowish blotches on the upper leaf surfaces. Scrape off minor infestations with your fingernail. Prune out badly infested growth, or use a soft brush and soapy water to gently scrub the scales off the stems. Control scales by spraying insecticidal oil during the growing season.

The lower leaves start to turn yellow and overall growth slows down in rosemary plants that are under fertilized or rootbound. Bump the plant out of its pot and check the roots. If they are dense and have been circling around and around the inside of the pot, it's time to either clip them back and return the plant to its original pot, or trim them and repot it in a larger container with fresh soil mix.