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Verbena with mildew?

susiebowersusiebower Posts: 138
in Problem solving
Hi - another newbie question! I sent off for the GW offer including some plug plants of verbena. Following advice, I didn't plant them in the garden but put them into bigger pots and they seemed to thrive. But recently their leaves are covered in what looks like powdery mildew. Any advice or thoughts on what's best to do - should I just dispose of them, or should I try cutting them right down to get rid of the mildewed leaves? (They are probably about 12" tall). I'm also worried the mildew might spread to other plants. 
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  • FairygirlFairygirl Posts: 55,117
    Have you got a photo @susiebower? 
    I've never heard of them getting mildew - which type of verbena are they though?
    It's a place where beautiful isn't enough of a word....



    I live in west central Scotland - not where that photo is...
  • B3B3 Posts: 27,505
    Do you mean verbena bonarensis? Most of mine have mildew by this time of year.  If they're badly affected, I cut them back or pull them out. But then I have plenty of seedlings to spare. If they just have a bit, I ignore it and cut them back if the seed heads go soggy or in the spring.  I'd just pick off the worst leaves off your plants and see how they look next year . The mildew won't spread. Although some other plants like pulmonaria are prone to it too. It's usually caused by dry conditions.
    In London. Keen but lazy.
  • susiebowersusiebower Posts: 138
    @Fairygirl - yes, it's verbena bonarensis. I've looked it up and seems it's quite common.  @B3 - that's interesting. I'll try picking off the worst leaves and see how they go. Very reassuring to know the mildew won't spread. :)
  • FairygirlFairygirl Posts: 55,117
    Ah - never had that problem with it. Probably different conditions though   :)
    I'd agree - just snip the duff bits off, and they should be fine.
    Yes - mildew is plant specific, so it won't spread to other plants of a different species. 
    It's a place where beautiful isn't enough of a word....



    I live in west central Scotland - not where that photo is...
  • susiebowersusiebower Posts: 138
    Thanks, @Fairygirl - will try it and see! :)
  • rossdriscoll13rossdriscoll13 Posts: 234
    @susiebower powdery mildew won’t harm your verbena it’s just superficial. If you are really worried you can spray it with Rose Clear Ultra but your plants will be perfectly fine and return unscathed next year.
  • GardenerSuzeGardenerSuze Posts: 5,692
    edited October 2022
    @susiebower If you live in the south and your Verbenas are growing in full sun and dry soil they can develop mildew in very dry weather. In these conditions you should also get lots of seedlings so plenty for next year. I have just removed some in my garden that were mildewed. I am confident that there will be lots more next year, I purchased one plant twenty years ago and they always appear somewhere in the border. They are lovely in the winter months too although they can get blown about.
    Further north is different some gardeners will put them under glass.I wouldn't resort to chemicals let them sort themselves.
    I have worked as a Gardener for 24 years. My latest garden is a new build garden on heavy clay.
  • bédébédé Posts: 3,095
    edited October 2022
    susiebower said:
    @Fairygirl - yes, it's verbena bonarensis. I've looked it up and seems it's quite common.  @B3 - that's interesting. I'll try picking off the worst leaves and see how they go. Very reassuring to know the mildew won't spread. :)
    Common, yes.  Top fashion at the moment, it has been the last 5 years or so.

    I have in the past included Verbena bon. at the front of my shade-and-shrub border, but it never really thrived, nor did any seed germinate.  A shame.

    I believe mildew is a whole family of fungi with different host plant preferences.  So it probably won't spread widely.  I always think of mildew as a problem of damp, but on plants it seems to be a problem of dryness.  I have had it particularly badly this year on my Acanthus spinosus (?spinosissimus) but it didn't spread the my A mollis, or balcanicus/hungaricus.

    Downey mildew seems to have cropped up this summer on several forum threads.
     location: Surrey Hills, England, ex-woodland acidic sand.
    "Have nothing in your garden that you don't know to be useful, or believe to be beautiful."
  • DovefromaboveDovefromabove Posts: 88,147
    edited October 2022
    I don’t think I’ve ever seen Verbena bon at this time of year without some powdery mildew. It’s nothing to worry about and certainly not a reason to use a fungicide. 

    It’s worth beating in mind that over-use of fungicides in agriculture and gardening is causing real problems for our health, in a similar way that overuse of antibiotics has done. Some formerly mild fungal human health conditions are becoming life-threatening because of resistance. It’s worrying. 

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





  • susiebowersusiebower Posts: 138
    @Dovefromabove @GardenerSuze @bede @rossdriscoll13 Thanks so much, all. This is really reassuring. And no way would I use pesticides on it - it was either a case of throwing it out or pruning it or waiting (am trying to be organic as poss in my garden). The verbenum in pots were standing next to salvia (also in pots) and so far (touch wood) the mildew is only on the verbenum. 
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