Looks like we have powdery mildew on one of our potted rose bushes. What should I do?
We all think that powdery mildew is from dampness; it is from drying out - quite the opposite. It will not kill the plant it just doesn’t look nice. I have it one one of my bonsai maple seedlings as they tend to dry out quickly. Next year be sure to keep the roses well watered. The rose may be pot bound and as much as you think you are watering it well, the water may just be running off the surface and not soaking into the root ball. Set it in a tub of water to soak. Try this spray: combine one tablespoon baking soda and one-half teaspoon of liquid, non-detergent soap with one gallon of water, and spray the mixture liberally on the plants. Mouthwash. The mouthwash you may use on a daily basis for killing the germs in your mouth can also be effective at killing powdery mildew spores. (got it from the internet but have heard of the baking soda trick before).
Good advice. I have used that recipe for years, and to kill aphids I use a TBSP of both liquid dish washing detergent and vegetable oil in a gallon of water. Works instantly
Thanks - this formula works very well!