California is the top peach-producing state in America, growing around 800,000 tons of peaches per year. Trees are usually trained into a wide, open vase-shape allowing sunlight to reach as many peaches as possible. Pruning takes place in growing season when new shoots appear, as well as during dormant periods. However, according to a study by researchers at the University of Georgia, peach trees in California shouldn't be pruned from October to January to avoid peach tree short life, or PTSL.
Cut back all main shoots from year-old trees in early April. Leave, however, four shoots intact, equally spaced around the tree trunk. These will develop into the main structural branches to build the vase-shape around. Remove any dead twigs.
Pinch off the ends of the structural branches in early June so that they are around 3 feet long, according to the University of California. Allow side shoots to bud off from these branches, but prune any extra shoots that appear on the trunk.
Prune any shoots that appear growing straight up from the center of the tree, or vertically up from the structural branches.
Snip off any central branch and shoot growths in mature, fruiting trees. Lop off the ends of structural branches to keep trees at a manageable height. Cut back any branches that grow back toward the trunk or start to bunch together with other stems.
Thin out peaches four weeks after the tree first blooms in late spring. Pull developing fruit off the branches or prune the fruit stems so that there is a gap of around 6 inches between peaches, according to Clemson University.