For disease PREVENTION on annual bedding plants and perennials we recommend using products that contain Neem oil, which can also be used on fruits, flowering plants, ornamentals, and roses to prevent black spot, rust, leaf spot, and powdery mildew. Neem oil also works to control many harmful insects. Safer Company makes a 3-in-1 product, that includes insecticidal soap for insect control, sulfur for fungicide, and neem oil. This spray does not harm beneficial insects and can be used on vegetables or any other plants.
IMPORTANT: If an annual bedding plant planted in an annual flowerbed dies, and the bed is full of all the same type plant, remove immediately to stop any spreading of disease throughout the entire flowerbed.
When and if you spray your annual and perennial plants for preventitive purposes, make sure to wet as much of the foliage as is possible.
Homemade Recipes for Treating Fungal Diseases
If you are growing annuals or perennials in mixed conatiners or beds, and one variety of plant looks as though it may have a disease, you can use the following homemade recipes as a possible remedy:
- Mix two tablespoons of baking soda into a quart of water. Pour into a spray container and spray affected areas. Repeat this process every few days until problem ceases.
- Powdery Mildew: Mix equal parts milk and water and spray on infected plants. Three treatments a week apart should control the disease.
- Insects and Fungal Diseases: Combine one tablespoon of cooking oil, two tablespoons of baking soda and a few drops of Ivory soap into a quart of water. Pour into a spray container and spray foliage.
Disease Prevention Tips for Annuals
- Water plants at the base to avoid splashing water on leaves.
- Water or irrigate plants in the morning hours to allow any water that might splash on foliage to dry during the day. Water left standing on foliage overnight can quickly cause development of fungus and disease on foliage and flowers.
- Plant most annuals and perennials in well-drained soils to avoid root rot, leaf spot and other plant diseases caused by wet feet. Some perennial plants actually prefer wet soil.
- Space plants properly instead of overcrowding. Overcrowding doesnt allow for good air circulation; one of the best preventive measures for disease and fungus.
- Make sure you select plants that have demonstrated tolerance to disease - especially if you garden in a hot and humid climate.
- Allow beds and containers to dry out a little before watering. Do not water so much that the soil remains consistently wet. Overwatering plants is the number one cause of death.