KC Gardens

Powdery mildew on discount hydrangeas


I just purchased and planted some Forever and Ever Blue Heaven hydrangeas at a steep discount. Appears they have powdery mildew. Any suggestions for a product to help remove it? - Carolyn -


  1. 9 months, 2 weeks ago

    Powdery mildew is best controlled culturally by providing good air circulation, and avoiding overhead watering, both of which this hydrangea may not have enjoyed at the point of purchase.

    Once a leaf is infected, a fungicide will not kill the mildew, but rather serve to protect the new growth. You can use Neem or a fungicide rated for Powdery Mildew.

    The problem now is that the temperature are very high, such that it is very important to read the label as to application temperatures.

    As your plant has obviously been under stress, I might give it a shot of starter fertilizer, water at ground level, make sure to plant it where it will have very good air circulation, and let the plant grow out of its problem. You can prune off some of the infected leaves, but be sure to put them in the trash, don’t compost.

    Deep discounts are great, but we take a chance, and success is all the sweeter. Good luck.

    Carole Johnson County Extension Master Gardener

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