Why Does My Hydrangea Look Unhealthy?

Are the leaves wrinkled and discolored?

Are the leaves tied together over flower buds?

Are the leaves deformed and the shoot tips blackened?

Do the leaves have a powdery white coating on them?

Are the hydrangea flowers rotting?

Are the leaves stippled with yellow and the foliage is webbed?

Have the leaves and flowers been skeletonized?

Are the leaves and flowers browned and wilted?

Wrinkled and discolored leaves are caused by aphids. These tiny insects can vary in color, green, pink, black, gray and completely white. They cluster under leaves and on growing tips where they feed on plant sap. Leaves, stems and buds get distorted and later leaves and flowers drop from the plant. You can control them by washing them off the plant with water spray. Insecticidal soap should be used with severe infestations.

Hydrangea leaftier is a green-bodied, brown-headed caterpillar that causes the foliage to become ragged, turn brown and die. If the infestation is light, break open the “envelopes" and pick off the caterpillars. For heavier infestations, spray plants with BTK.

Tarnished plant bugs inject a plant-deforming toxin as they feed on young leaves. Trap them with white sticky traps or treat plants with a commercial pyrethrin spray or dust in the evening to control severe infestations. The best way to prevent this pest is through a thorough fall and spring cleanup. This will prevent it from overwintering.

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 most common cause for rotting flowers in Hydrangea is the fungal disease Botrytis blight. Other symptoms include brown spots that may appear on leaves. You can only prevent Botrytis blight disease by planting hydrangeas 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.

Spider mites often cause problems for hydrangeas. 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 or pyrethrin.

Skeletonized leaves and eaten flowers are caused by Japanese beetles (metallic-brown beetles) or Rose chafers (reddish-brown beetles). Handpick adult beetles into a can of soapy water but make sure to wear gloves as Japanese beetles are blister beetles. Apply parasitic nematodes to the soil to limit beetle grub populations. Use pyrethrin powder as a last resort.

Browned and wilted leaves in hydrangeas usually indicate bacterial wilt disease. This disease can spread quickly, killing the plant in hot weather. Remove infected parts as soon as you see them. Destroy seriously infected plants.

If the leaves have small brown spots on them, the most likely cause is the fungal disease - Rust. Infected leaves have bright orange spots underneath and pale yellow spots on the upper surfaces. They eventually wilt and drop. Remove and destroy leaves infected with this fungal disease. As a last resort, spray or dust with sulfur, repeating as needed.