Climbing Hydrangea

Asked August 17, 2019, 9:14 AM EDT

Hello! There is something all over my climbing Hydrangea. They are white and hard and prolific. They're even all over the brick where the Hydrangea is climbing.

Baltimore Maryland vines cottony camellia scale climbing hydrangea

3 Responses

This looks like cottony camellia scale on the foliage. This is a soft scale, a sucking insect. Honeydew and sooty mold are the major problems caused by this insect.
In june, females die and may fall off, leaving only white ovisacs. Immatures hatch through June and remain on the underside of leaves or bark through the winter.
At this point, we recommend that you spray with a dormant oil after leaf drop. Follow label directions.

Marian

Thank you so much. Now that the leaves are dropping I am shocked and a bit worried about what I am seeing. There are literally thousands of them. Should I be worried?

This looks like cottony camellia scale. There is one generation a year and immatures remain on the leaves /bark through the winter. At this point we recommend that you rake any fallen leaves and dispose of in the trash.
Now is a good time (this week) to spray with a dormant rate of horticultural oil. Follow label directions. You may not get 100% control but should help to control a lot of the overwintering scale.

Monitor the vine in the spring. Ovisacs are placed on the underside of leaves in May and crawlers appear in mid-June and summer on the leaves. You can apply double-sided sticky tape to branches in May to monitor. If need be, you can apply a summer rate of horticultural oil to control the crawlers.
Here is our website for more information https://extension.umd.edu/hgic/topics/cottony-camellia-scale-shrubs

Marian