Ask a Question forum: Is this powdery mildew on my Phlox?

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zone 5 - northern Illinois
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ninabee
Jul 31, 2017 6:52 AM CST
Planted this early in the summer. It's not looking very good. From what I've read, sounds like powdery mildew. Can someone confirm this from looking at the picture I've attached. I've never dealt with it before. If it is p.m., how do I get rid of it? Should I cut it all down since most of the plant is infected?
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Name: Daisy I
Reno, Nv (Zone 6b)
Not all who wander are lost
Garden Sages Plant Identifier
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DaisyI
Jul 31, 2017 3:02 PM CST
It does look like Powdery Mildew, caused by cool, damp weather. Try spraying it with a fungicide - that may help.
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and proclaiming...."WOW What a Ride!!" -Mark Frost

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Name: Philip Becker
Fresno California (Zone 8a)
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Philipwonel
Jul 31, 2017 6:38 PM CST
White is powdery mildew. Hose off in morning, a few/several days. That will take care of it.
I'm concerned about black spects on leaves. Also brown blotches on undersides of leaves.
Anything i say, could be misrepresented, or wrong.
zone 5 - northern Illinois
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ninabee
Aug 2, 2017 10:26 AM CST
I am also concerned about the black spots. I thought they were from the mildew. Am I wrong? Anyone know what's causing the black spots? I love phlox and I really want this plant to survive.
Name: Philip Becker
Fresno California (Zone 8a)
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Philipwonel
Aug 2, 2017 10:47 AM CST
If no bugs. It could be fungus. Or it might clear up on new growth, after you take care of mildew. Shrug!
Anything i say, could be misrepresented, or wrong.
Name: Daisy I
Reno, Nv (Zone 6b)
Not all who wander are lost
Garden Sages Plant Identifier
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DaisyI
Aug 2, 2017 11:22 AM CST
It is mold growing with the mildew:

http://www.gardeners.com/how-t...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and proclaiming...."WOW What a Ride!!" -Mark Frost

Webmaster: osnnv.org
Name: Sue
Ontario, Canada (Zone 4a)
Daylilies Birds Enjoys or suffers cold winters Native Plants and Wildflowers Butterflies Annuals
Region: Canadian Keeps Horses Dog Lover Plant Identifier Garden Sages
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sooby
Aug 2, 2017 11:27 AM CST
Powdery mildew produces blackish spots which are fungal fruiting bodies. I'm not sure that's what is in the pictures though. When phlox get powdery mildew they can look pretty terrible all round with a lot of yellowing etc. You might want to look into powdery mildew resistant cultivars. As Daisy suggested, you can use a fungicide if you wish - while it won't "heal" the already affected leaves it may slow its progression to the new leaves.

This article on powdery mildew from the Missouri Botanical Garden may help:
http://www.missouribotanicalga...
Name: Sue
Ontario, Canada (Zone 4a)
Daylilies Birds Enjoys or suffers cold winters Native Plants and Wildflowers Butterflies Annuals
Region: Canadian Keeps Horses Dog Lover Plant Identifier Garden Sages
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sooby
Aug 3, 2017 11:48 AM CST
Thought you might like to see a bad case of powdery mildew on phlox from a garden near where I live. I took these with my phone this morning, you might think yours are not so bad after this Smiling The tops of the plant were still clear of mildew and the plant will be flowering soon. The particular plant does this ever year, some worse than others.

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Name: Carol
Santa Ana, ca
Sunset zone 22, USDA zone 10 A.
Charter ATP Member Hummingbirder Lover of wildlife (Black bear badge) Orchids Region: California Plant Identifier
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ctcarol
Aug 3, 2017 12:29 PM CST
Sure looks like it to me.
zone 5 - northern Illinois
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ninabee
Aug 4, 2017 7:41 AM CST
Sooby, your plant still produces flowers? Mine is struggling to produce. I'm going to cut it all down today and spray the remaining growth with a fungicide now and then religiously in the spring. Hoping it will do better next year. I have 2 other phlox plants that are doing well, no signs of mildew. Like I said in my original post, this was a new plant. My guess it was already infected when I purchased it.
Name: Sue
Ontario, Canada (Zone 4a)
Daylilies Birds Enjoys or suffers cold winters Native Plants and Wildflowers Butterflies Annuals
Region: Canadian Keeps Horses Dog Lover Plant Identifier Garden Sages
Image
sooby
Aug 4, 2017 10:02 AM CST
That particular one does still produce flowers (it's not mine but in a garden I'm very familiar with). Another one struggles to some years. Since the disease is airborne it doesn't have to have been infected when you purchased it. You'll need to use preventative fungicide every year on it most likely if you can't live with the mildew, so it might be easier to get rid of it and replace with one that is resistant, like your other two apparently are.

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