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UC Cooperative Extension Ventura County
669 County Square Dr. Suite 100
Ventura CA 93003
Phone: 805.645.1451
Fax: 805.645.1474

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Hydrangea Virus

There are three viruses reported to infect hydrangea - Hydrangea Ring Spot V., Tomato Spotted Wilt V., and Hydrangea Latent V. Without doing some expensive laboratory testing, it is not possible to be specific as to which virus is present. All three viruses are present in California.
There is no cure for viruses in plants. The infection is systemic, so all tissues in the plant carry the virus(es). Some viruses are very disfiguring to plants, some show only mild symptoms and have little effect on “normal” plant growth and flowering. You will have to decide if your plant has been or is aesthetically damaged to the point where it is no longer an asset to your garden. If your choice is removal and replacement, remove as many of the roots as possible – they are also infected. I would wait a year before replanting another hydrangea in the same site. Residual roots take some time to deteriorate, and root contact between old and new plant roots could affect transmission to the new plant.
If you keep the plant and also have other hydrangeas in your yard, be sure to prune or take flowers on the infected plant last. Then disinfect the shears or clipper before the next visit to the hydrangea patch. Viruses can be transmitted in plant sap. So sap on the cutting shear blades can be infective.