Why Does My Allysum Looks Unhealthy?

Are there any white downy growths on the underside of the leaves, foliage may be yellow?

Are the leaves covered with white powdery patches?

Are the leaves yellowing, wilting and, dying?

Are there any dark lesions on stems, roots may be rotted?

Are the flowers covered with gray mold, leaves may be blotched or discolored?

Are the plants missing?

Leaves, stems, and flowers infected with fungal disease, Downy mildew, have spots covered with white fuzzy growth on the undersides. Spray plants with copper when symptoms first appear. Thin your flowers to increase airflow between them.

White, powdery coating on the leaves is caused by a 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.

Yellow leaves that wilt and die usually indicate Root rot in sweet allysums. This disease is caused by both fungi and bacterias. 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.

Dark lesions on stems are caused by Stem rot. This disease can be caused by both bacterias and fungi. Remove and destroy all infected plants. Thin plants to ensure good air circulation. Water plants from below so the foliage can stay dry. Solarize the soil before replanting.

Gray mold on flowers is probably caused by fungal disease - Botrytis blight. You can only prevent Botrytis blight disease by planting flowers in areas with good air circulation. Water plants sparsely. Infected plants should be removed. Spray weekly with a copper fungicide until the disease is under control.

If leaves and stems have been eaten whole the problem may be deers. If deer frequent your property then your sweet allysums are in jeopardy. Barriers provide the most reliable long-term protection from deers.

Sweet alyssum plants require little maintenance. While alyssum is relatively maintenance-free, it will do poorly on boggy sites and where inadequate moisture is provided.