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Blue Vervain issues #871132

Asked June 02, 2024, 11:27 AM EDT

Good morning! I’m looking for some help please. My Blue Vervain had what appeared to be powdery mildew. I tried the hydrogen peroxide spray (9 parts water to 1 part 3% hp) and now this is what I have. Couple questions. Is this still showing signs of powdery mildew or is this a different issue? What would you recommend my next step be? I have been holding off on planting them in my garden until they are healthy. Good idea or should I cut them down and get them planted? Thanks in advance for the help!

Scott County Minnesota

Expert Response

I don't see any powdery mildew in your photos. I’m not sure why you sprayed them with peroxide or where that advice came from. 

If it was powdery mildew, by the time you see the evidence treating it is too late. We have had a very wet, warm spring and this provides good conditions for powdery mildew to thrive. 

I would go ahead and plant them. Be sure to give them enough room to grow and get air circulation. Do not fertilize them. Remove any leaves that show signs of the powdery mildew and dispose of them. Do not put them in your home compost pile. 

https://extension.umn.edu/plant-diseases/powdery-mildew-flower-garden#:~:text=Powdery%20mildew%20is%20a%20common,reduce%20plant%20growth%20and%20flowering.

Deb Reierson Replied June 02, 2024, 6:16 PM EDT

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