Phlox Disease - Ask Extension
My phlox has become diseased. Please see the attached photo. Is this because of the very wet spring?
I have cut down the stalks to very small lengths...
Knowledgebase
Phlox Disease #873439
Asked June 17, 2024, 12:46 PM EDT
My phlox has become diseased. Please see the attached photo. Is this because of the very wet spring?
I have cut down the stalks to very small lengths, but wonder if there is something else I should do. Also, how can I prevent this happening again?
Thank you,
Mary
Montgomery County Maryland
Expert Response
Thank you for submitting your garden and landscaping questions to the University of Maryland Ask Extension Service.
Oh dear, your phlox plants are covered with powdery mildew which is a fungal disease on susceptible plants . Please see this UMd Extension webpage on powdery mildew https://extension.umd.edu/resource/powdery-mildew-disease-flowers/.
There is not a lot that you can do to control this problem except to severely cut them back, open spaces near your plants to provide increased airflow around them, water your phlox plants at the soil surface and try not to wet foliage, sprinkle baking soda on foliage (a natural fungicide) or spray foliage with horticultural oil (when temperatures are below 85F degrees).
Probably the best way to deal with this problem is to remove susceptible phlox plants altogether and replace with phlox varieties that are resistant to powdery mildew. Google 'Mt. Cuba Center Plant Trials' and search for Phlox. Make a list of the best varieties and then visit or call local garden center stores to see if they have any of these varieties, or search online to find them.
Good luck in your garden adventures. Thanks; Christopher
Oh dear, your phlox plants are covered with powdery mildew which is a fungal disease on susceptible plants . Please see this UMd Extension webpage on powdery mildew https://extension.umd.edu/resource/powdery-mildew-disease-flowers/.
There is not a lot that you can do to control this problem except to severely cut them back, open spaces near your plants to provide increased airflow around them, water your phlox plants at the soil surface and try not to wet foliage, sprinkle baking soda on foliage (a natural fungicide) or spray foliage with horticultural oil (when temperatures are below 85F degrees).
Probably the best way to deal with this problem is to remove susceptible phlox plants altogether and replace with phlox varieties that are resistant to powdery mildew. Google 'Mt. Cuba Center Plant Trials' and search for Phlox. Make a list of the best varieties and then visit or call local garden center stores to see if they have any of these varieties, or search online to find them.
Good luck in your garden adventures. Thanks; Christopher
