Capsid bug

Capsid Bug on my Hydrangea Annabelle

Question from Ann Brooks

I am very new to gardening, but think I have identified that I may have capsid bug on my newly planted Hydrangea Annabelle. The edges of the leaves are going black and dry, as are some of the stems and the outer edges of the new flower buds. Could you advise what the best treatment is. I have cut back all the stems and leaves that were badly affected, but the problem, although not a prevalent, still seems to be present