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The Monarda I purchased a month ago is starting to get powdery mildew. I read this plant is susceptible to getting it but I’ve done all I can to prevent it.

Is it a case of removing affected leaves/stems or should I be more drastic and cut down the plants?



  • punkdocpunkdoc Posts: 14,966
    I would just water them more.
    How can you lie there and think of England
    When you don't even know who's in the team

    S.Yorkshire/Derbyshire border
  • Wouldn’t over watering promote more mildew?
  • DovefromaboveDovefromabove Posts: 87,935
    Powdery Mildew isn't like damp mould.  It's a fungal condition which attacks stressed plants ... usually plants that are stressed by drought at the roots.  There are many types of Powdery Mildew, each specific to it's own type of host plants.  

    Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.

  • Ah, ok, thanks. So if I keep on top of watering, the plants should be ok and it won't spread to nearby plants? 
  • I grow Monarda and it develops mildew after dry weather, which we've had of late. In wetter summers it doesn't. As @Dovefromabove said, it's all down to irrigation. It won't spread to other plants.
  • Many thanks all, you've put my mind at ease. Hopefully the wet weather we've got now will help the Monarda!
  • DovefromaboveDovefromabove Posts: 87,935
    Give it a bucket of water as well ... poured slowly over the root area so that it soaks in rather than runs off the surface ... it's surprising how dry the soil can be down at root level, even after 24 hours or more of rain.   I did some planting a few days after all that rain in May was over ... three inches below the surface the soil was like dust.  :o

    Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.

  • Will do, thanks. I’m always wary of over-watering and often find it hard to judge when/how much to water. I usually put a wooden skewer in the ground and see how discoloured it is once removed. If it come out slightly discoloured, with fragments of soil stuck on it, I assume, maybe wrongly, that is doesn’t need watering?

    Maybe I need a more accurate method!

  • DovefromaboveDovefromabove Posts: 87,935
    Your finger is far more sensitive than a wooden skewer .... stick you finger in up to the second joint ... if it doesn't feel damp down there most plants will need watering.  :)

    The other thing is a good watering once or twice a week is so much better than little and often ... just dampening the surface keeps the roots up near the surface, and then they can get overheated when the sun is strong.  If the roots go down to reach water they're protected from the heat of the sun.  :)

    Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.

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