Peach trees should be pruned when the buds swell and begin to pink, apple trees should be pruned during their dormant season in late winter. Most fruiting trees should be pruned when dormant.
Peach trees should not be pruned during the dormant season because the cold makes them susceptible to dieback. It can also cause them to be less cold-hardy overall. When pruning, it is better to prune them late rather than early. Apple trees dormant season is late winter or very early spring. Without proper pruning, fruit trees will not produce the abundant amount of fruit they are capable of producing.