Answer: Based on your description I am not absolutely acertain what you are seeing, but it might be a case of scale insects. These can be treated with insecticidal soap when they are in the soft crawler stage, or smothered with an oil spray during the winter. I would suggest you consult with your local county extension for a more specific diagnosis of the problem. If a chemical control is needed, they will have the most up to date information on what to use and how/when is best to use it for maximum results. Good luck with your hydrangea!
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