Today, espalier refers to a process of growing a tree flat against a wall. This has a very dramatic effect on any garden and such trees tend to become a garden's focal point. There is a lot of work involved in mounting a tree flat against a wall and then pruning it properly to keep it looking nice. An espalier pear tree can be pruned so it will still produce fruit, but expect to spend a lot of time and energy maintaining the look of your tree. Major espalier pruning should take place in late winter or early spring before new growth appears, although some pruning will take place throughout the year.
Make sure all wires designed to hold the tree close to the wall are in place and that broken wires have been repaired. Loosen ties holding branches to the wall if the branches have grown so thick that the ties are now cutting into the branches.
Remove all dead or diseased branches. Cut branches off just beyond the node where the branch grows out of the trunk. Cut all smaller branches off where they connect to major branches.
Decide on a design style for your tree. Some gardeners prefer a free-flowing style but others like a more ridged style such as a candelabra, a tiered look, a basket weave, a fan, a diamond motif or others. Draw the way you want your tree to look on a piece of paper.
Tie young, supple branches to your wire frame using plastic ties so they fit the pattern you have decided upon.
Cut branches that do not fit the look you have decided upon.
Cut the tips of branches and the tip of the top of the tree in order to make the tree conform to the picture you have drawn of how you want the tree to eventually look.
Pinch new growth and clip the tips of branches throughout the growing season in order to encourage the tree to grow in the pattern you have decided upon. This is a long and involved process. Do not do any major pruning late in the summer, as this could encourage new growth that will not have time to harden off before the arrival of winter.