Oak leaf hydrangea
When do you prune or cut back this bush? It is severely overgrown and needs cut back.
Now is the perfect time to prune oakleaf hydrangea, assuming yours is done flowering. After flowering, prune back each branch about halfway. It should still have time to produce new growth later this fall that will allow it to bloom next summer. Or, if you prefer, you can cut it all the way to the ground. In this case it will not bloom next year but should the year after.