Hydrangea disease? - Ask Extension
Black spots on my hydrangea leaves (and stems, too). I cut lots of them away. Anything I can do to save this one?
Knowledgebase
Hydrangea disease? #877968
Asked July 19, 2024, 5:58 PM EDT
Black spots on my hydrangea leaves (and stems, too). I cut lots of them away. Anything I can do to save this one?
Marion County Oregon
Expert Response
Dear Joy,
Thank you for contacting us about your hydrangea. It does not appear to show evidence of disease or pest damage. I suspect the dark dry spots are a result of excessive heat and/or sun, or perhaps the soil is allowed to dry out too much between waterings.
I recommend watering slowly and deeply when the soil feels dry about 2 inches deep. Also, use about 3 inches of organic material as mulch over the root zone. This will mitigate heat and moisture loss from the soil. Another way to test the soil moisture is with a screwdriver:
https://youtu.be/HrZNPaBtmtw
Do not fertilize in the summer since this may encourage new growth that might not be able to withstand the hot weather.
I hope this information is helpful. Please write again any time you have a gardening question.
Thank you for contacting us about your hydrangea. It does not appear to show evidence of disease or pest damage. I suspect the dark dry spots are a result of excessive heat and/or sun, or perhaps the soil is allowed to dry out too much between waterings.
I recommend watering slowly and deeply when the soil feels dry about 2 inches deep. Also, use about 3 inches of organic material as mulch over the root zone. This will mitigate heat and moisture loss from the soil. Another way to test the soil moisture is with a screwdriver:
https://youtu.be/HrZNPaBtmtw
Do not fertilize in the summer since this may encourage new growth that might not be able to withstand the hot weather.
I hope this information is helpful. Please write again any time you have a gardening question.
