Asked on May 3, 2017

My Knockout Roses have developed powdery mildew, how do I treat this?

Shawna BaileyJanet PizaroGrace Robertson


i have 25 rose bushes throughout my yard. Only 6 bushes are showing signs of this disease. Please help!
5 answers
  • Adrian
    on May 3, 2017

    You have to spray them with a fungicide- there are many of them so you'll need to ask someone at your local gardening supply company. The one that may work best and is most cost effective is the type that you mix and put into a sprayer. If you only have a few small ones then a ready mixed spray already in the sprayer bottle will do. The only issue is that you usually have to spray them down and then go back in one week and do it once more so make sure you have enough before you begin.
  • Vickie
    on May 3, 2017

    Thank you! I will see the local nursery for guidance.
  • Grace Robertson
    on May 3, 2017

    I have used Sevin powder with success. A very light dusting on the leaves, Just be very careful when using the powder. I suggest that you wear a mask when applying it to your roses. A little powder will go a long way.
  • Janet Pizaro
    on May 3, 2017

    Use a systemic treatment for roses. Bayer is a recommended product for insect,fungus and a fertilizer.
  • Shawna Bailey
    on May 4, 2017

    I've used Bayer with success
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