You can prune healthy yews (Taxus spp.) back quite severely with no problem. You can easily reduce their size by one-half to three-quarters. Such severe pruning is best done in early spring so they have spring and summer to recover.
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They will respond by throwing up a lot of new shrubclean.barted Reading Time: 3 mins. Feb 22, Yews are one of the easiest evergreens to prune and reliably sprout on bare wood, so if you cut your yews back severely or shear them into a hedge form, they'll fill out quickly.
Late winter or. 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. Prune evergreen shrubs, such as juniper and yew, in late March or early April before new growth begins.
Light pruning may also be done in mid-summer. Avoid pruning evergreen shrubs in the fall. Fall pruned evergreens are more susceptible to winter injury. The most ideal time to cut a yew hedge is in early spring, around about March. It will then start shooting again in April. You can easily cut yews right back, down to the old wood - they can tolerate that. After pruning, you would be looking through a hole, however, which is not that attractive in a hedge that is then merely waist-high.
Yews unlike many other evergreens will tolerate severe pruning. But brace yourself, it can take one or two seasons for the new needles to develop and cover the old wood. Wait until early spring, before growth begins. The pruning wounds will close more readily as the plants begin to grow in spring.