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Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

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Wednesday - August 07, 2013

From: Newport, RI
Region: Northeast
Topic: Non-Natives, Diseases and Disorders, Pests, Shrubs
Title: Possible maple scale on non-native mophead hydrangeas from Newport RI
Answered by: Barbara Medford

QUESTION:

I have a mophead hydrangea that has small white cottony tufts under the leaves and on the stems. I believe this is maple scale. Is there a home remedy I can use to rid this disease?

ANSWER:

There are 4 members of the  Hydrangaceae family in our Native Plant Database, indicating that they are native to North America. They are: Hydrangea arborescens (Wild hydrangea), Hydrangea cinerea (Ashy hydrangea), Hydrangea quercifolia (Oakleaf hydrangea) and Hydrangea radiata (Silverleaf hydrangea). Hydrangea macrophylla, (Mophead hydrangea) is native to China and Japan and therefore out of our range of expertise. However, we know that many are grown in the United States and some Internet research turned up some information that will perhaps lead you to a solution to your problem. In response to your question, no, we do not know of any "home remedy" for your problem, and in fact, don't know for sure what your problem actually is. Because local gardeners are more apt to know about locally grown plants, we suggest you contact the University of Rhode Island Cooperative Extension Office to learn if others are experiencing the same difficulties. Then, follow these links to other university and national sites on specifics of the problem:

University of Rhode Island Master Gardeners

Alabama University Cooperative Extension System Diseases of Hydrangea.

United States National Arboretum Pests and Diseases of Hydrangea macrophylla

Washinton State University Extension Scale Insects on Ornamentals

 

From the Image Gallery


Wild hydrangea
Hydrangea arborescens

Oakleaf hydrangea
Hydrangea quercifolia

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