This is the year I remember to deadhead (or cut back) Boltonia and some Monarda. Do I just pinch a bit off the top (I'm a nervous about taking off too much)??? I want to stagger the flowering time and, make the Boltonia less tall and gangly.

Also, have an Endless Summer Hydrangea that has about 8 inches of new growth coming up from the crown. Is it ok to cut the branches remaining from last year?? And, can I cut them to the first new growth, or lower??