What is this insect?
We cannot accurately identify the larvae in the photos. It is possible it could be a looper, a type of caterpillar, which is a generalist feeder. Another possibility is the Rose of Sharon Moth, caterpillar.
The angle of the photo is odd. Other factors include - the larvae may have just molted and the color has not formed yet. Also, if the larvae is not moving it could be diseased or dead. In any event, monitor the affected shrubs next season, and send us photos as soon as you notice symptoms.