Browing hydrangea leaves

Asked May 29, 2018, 2:02 PM EDT

I just started to notice small brown spots on the lower leaves of my hydrangea, and possibly some yellowing if the lower leaves. Is this disease? If so how do I best treat it. Or could it possibly be a watering issues due to the extreme temps of 95+ the last several days?

Kent County Michigan trees and shrubs

1 Response

Hello,

The spots are caused by a fungus and look like Anthracnose to me. Daconil (chlorothalonil- active ingredient) is a fungicide that helps control it. Clean out all plant debris, diseased leaves and apply fresh mulch under bushes will help. (It looks like your mulch is fresh this year- if so, go ahead and keep it) Then begin applications of this fungicide in the spring and continue every 10-14 days or according to the label directions, depending on how much rain we are getting.

There are a few things you can do to prevent this problem in the future. Avoid overhead watering and water at the base of the plant early in the morning so that the leaves have time to dry during the day. Redirect any lawn sprinklers away from the perennials bed. Wet leaves going into the night cause the leaf surface to stay wet for a longer period of time and favors disease development. In fall after a freeze, pick up all plant debris and destroy. The fungal spores overwinter in debris left in the landscape. Finally, if the problem begins again start your fungicide spray at the first symptoms. Here is a reference for you

http://www.aces.edu/pubs/docs/A/ANR-1212/ANR-1212.pdf

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