There are several varieties of yew trees and shrubs commonly grown in the home landscape. There are upbright and bushy with spreading habits.As with most woody plants, the key to keeping your yew in good shape is early pruning. When the plants are installed, they should be given a good trim to establish growth lines. Choosing the right size and growth habit is important to minimise the amount of maintenance and ensure good care for your yew. If you want a low-growing plant, don't chose one of the upright cultivars. That said, yews do respond favourably to annual trimming and even the occasional severe cut back.
Maintain your cutting tools to ensure clean cuts and less strain on your hands. Pruning tools need to be sharpened between projects and sometimes during a big project. One or two passes over a sharpening stone or through a sharpening tool will be sufficient to give you a keen edge. Clean cuts cause less stress to the yew, minimise disease introduction through cuts, and allow the wound to seal more quickly. Wipe down the hinges and blades with machine oil to promote smooth operation.
Shape the upright variety of yew to one central leader. This Taxus normally has several trunks but will look best and be stronger with one thick stem. Prune off the peripheral small growth on the stems so you can identify the straightest centre one. Use a saw to cut out the others. Clean up the new central leader, and remove the lower twigs and branches up to a level that allows cleanup under the plant.
Cut out any dead, broken or diseased wood. Proper cuts are 1/4 inch from the branch collar, or where the wood joins the parent material. Cut at a 45-degree angle, and use the tool that will allow you to take the wood without straining yourself or crushing the plant material.
Identify the outline or "ghost line"of the plant. You need to decide where the top and sides will end. Start at the top ,cutting out plant material that will border this "ghost line." Make each cut down to the next growing point. Remove one out of every three or four shoots to thin the yew. Work downward, always keeping the base of the plant wider than the top for stability and to allow sunlight to all the leaves.
Use hedge trimmers for a formal, smoother line. Run them in a continuous motion from top to bottom to cut off smaller pieces of plant material that blur the outline of the plant. This is a finishing touch and is not necessary, but it is a quick way to keep the plant in line in between full pruning sessions.