How to Treat Black Spot on Roses

Do not compost the infected leaves, as this can cause the fungus to spread again. Instead, put them in a sealed trash bag and toss them in the garbage.

To make a DIY fungicide, mix 1 teaspoon of baking soda, 1 teaspoon of liquid dish soap and 1 quart of water. Pour the mixture into a spray bottle and shake well to create a natural fungicide. This solution alters the pH on the leaf surface, making it harder for the fungus to survive.

Neem oil is a natural and effective treatment for black spots on rose leaves. You can either mix neem oil with water in a ratio of 1 teaspoon of neem oil to 1 quart of water or follow the package instructions for accurate dilution. Once mixed, spray the solution evenly on the entire plant, including both sides of the leaves and stems.

Alternatively, you can also purchase a commercial neem oil spray for convenience. Neem oil not only treats black spots but also acts as a pesticide, offering protection against pests.

To prevent the spread of black spot fungus, water your roses directly at the base, focusing on the soil rather than the leaves. This method helps keep the foliage dry, reducing the risk of fungus. Drip irrigation is another great option, as it delivers water slowly to the soil, minimizing moisture contact with the leaves. Keeping the leaves dry supports healthier growth and encourages more blooms.

Make sure your rose bushes are spaced out evenly to allow good airflow. If the plants are too close together, trim some of the branches to create space between them. Good air circulation helps keep the leaves dry and prevents the fungus from spreading.

Spread a thick layer of mulch around the base of your rose plant. This helps prevent soil from splashing onto the leaves and spreading the fungus. Make sure the mulch doesn’t contain rotting wood, as this can cause other fungal problems like powdery mildew or root rot.

If the DIY methods aren’t working or the black spots on your rose leaves are spreading, you can try using a commercial fungicide. These products are designed to treat fungal infections more quickly and effectively. Be sure to follow the instructions on the label for proper use, including how much to apply and how often.