One of the most rampant diseases that affects rose plants is powdery mildew. It first manifests as small blisters on the surface of young leaves, and then a white powdery substance develops on the leaves, flower buds and stems. As the infestation increases, the leaves crumple and loose shape. Although powdery mildew will not kill your rose bushes, it detracts from their beauty. The disease tends to be more rampant in areas of high humidity. When leaves and blooms do not dry out well during the day, the dampness which encourages the disease. Below is a guide on how to cure your rose bush of this fungal infection.
Step 1 - Inspect
Carefully inspect the rose bush for signs of mildew. It is more likely to be found on new growth, though it can occur on older plant parts as well. Check foliage and blooms as well as leaves.
Step 2 - Prune
Prune areas that show evidence of the mildew. This will reduce the area to be treated. Be sure to trim at older plant parts as these tend to be more dense in growth. If the infection is not as serious, you can simply pluck off the affected leaves and buds.
Step 3 - Water Spray
If the mildew is mild or in its early stages, you can spray with water to get rid of it. Repeatedly spray affected parts until you clear off the mildew.
Step 4 - Prepare Solution
For more serious mildew attacks, spray with a specially-prepared mixture. Fill your container with water but leave 1/5 of the space for other additives. Mix in:
- ¼ cup white vinegar
- 1 tbsp. baking soda
- 1 tsp. cooking oil
- 1 tsp. dish detergent
Thoroughly shake the container so that the contents mix well.
Step 5 - Spray
Spray the affected rose bushes with the above mixture. It may be necessary to drench the bushes to get rid of the mildew. Continue with this treatment for some days until you are certain that all mildew has cleared off the plant.
Tips for Mildew Prevention
- Select a rose variety that is suitable for your climate and soil type. This will help reduce the incidence of mildew as well as other diseases.
- Plant your roses in an area that receives plenty of sunlight. Mildew is less likely to develop where sunlight is abundant.
- Improve air circulation around your rose bushes. When the airflow is good, it encourages the bush to dry out well. It also helps counter humidity.
- When you plant your rose bushes, be sure to leave adequate space between them to facilitate good airflow.
- Avoid over-watering as it will create conditions conducive to development of mildew.
- Prune regularly, especially at the center, to encourage airflow and sunlight.