Two of my well established Chinese fringe shrubs seem to have a disease.
What Kind of Disease on My Lorepetulum?
Certified GKH Gardening Expert
I'm not sure of the symptoms of your shrubs.
They may suffer from Powdery Mildew in moist growing conditions or Scale insects or Spider Mites.
A fungicide for Powdery Mildew treatment and a insecticidal soap if you see Scale or Spider Mites is a good plan of attack.