fungus on phlox - Ask Extension
My phlox is extensively covered with white raised patches that I'm guessing are a fungus. Can I treat this or do I have to cut down the phlox? Thank...
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fungus on phlox #935499
Asked June 14, 2026, 9:58 PM EDT
My phlox is extensively covered with white raised patches that I'm guessing are a fungus. Can I treat this or do I have to cut down the phlox? Thanks. See pictures.
Hennepin County Minnesota
Expert Response
It's likely powdery mildew. Compare here:
https://ag.purdue.edu/department/btny/ppdl/potw-dept-folder/2023/garden-phlox.html
At this stage, there is not much that can be done. Preventative measures include careful sanitation and water management (clean up debris, don't compost it, don't water overhead or at night, and so on). Read here:
https://extension.umn.edu/plant-diseases/powdery-mildew-trees-and-shrubs
https://extension.umn.edu/how/preventing-plant-diseases-garden
https://ag.purdue.edu/department/btny/ppdl/potw-dept-folder/2023/garden-phlox.html
At this stage, there is not much that can be done. Preventative measures include careful sanitation and water management (clean up debris, don't compost it, don't water overhead or at night, and so on). Read here:
https://extension.umn.edu/plant-diseases/powdery-mildew-trees-and-shrubs
https://extension.umn.edu/how/preventing-plant-diseases-garden
