Why Does My Lantana Look Unhealthy?

Are the leaves yellow and the plant looks stunted?

Do the leaves have white, cottony clusters on them?

Are the leaves mottled and with shiny black flecks on the undersides?

Do the leaves have a powdery white coating on them?

Are the flowers covered with gray mold?

Do the leaves have a black coating?

Does the whole shrub decline, leaves are stunted and pale and there is no new growth?

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 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.

Lace bugs are flat, dark-colored insects with lacelike wings that feed on the undersides of leaves. They cause leaves to turn yellow, then brown and eventually die. Treat plants with a commercial pyrethrin spray or dust if the damage is severe.

White, powdery coating on the leaves is caused by the fungal disease Powdery mildew. Powdery mildew usually appears in damp places. Encourage good air circulation around the affected plants by thining any surrounding plants. Water plants from bellow to keep foliage dry. Any affected leaves should be cut off and removed. Any commercial fungicidal spray will protect your plant from further infections.

The likely cause for these symptoms is the fungal disease - Botrytis blight. Other symptoms include brown to black spots that may appear on leaves and petals. You can only prevent Botrytis blight disease by planting lantanas in areas with good air circulation. Water plants so leaves can dry up before sunset. Infected plants should be removed. Spray weekly with a copper fungicide until the disease is under control.

Black coating on the leaves is caused by the fungal disease Sooty mold. This fungus grows on honeydew produced by aphids and scales. The black coating doesn't harm the leaves directly but it does reduce the intensity of photosynthesis. Sooty mold is best controlled by dealing with the insects that are producing honeydew. Remove honeydew and sooty mold from the leaves by wiping it with the damp cloth.

Root rot can be caused by overwatering or by poorly drained soil. There is no cure. Replant in well-drained soil or on a raised mound of soil.

Some environmental issues may have caused your plants sickly look. Lantanas need full sun and average, well-drained soil. Water deeply but let the soil dry out between waterings. Fertilize lightly, because overfertilization or excess water decreases bloom.