Pruning Yew in Summer

My yews are overtaking my walkway. I remember reading that they can be pruned mid summer. Is that right? How much can I prune off?

Yews, junipers, and arborvitae go into a semi-dormant phase in mid summer. Once the new spring growth has hardened off, turned the same dark green as the rest of the plant, you can do some pruning. This is the perfect time to clip back wayward branches and overgrown shoots by two thirds. Prune them back to an adjoining branch or above a healthy bud to maintain the plant's natural appearance. Save major pruning for late winter or early spring.