Wait for the pole beans to set pods. Pruning before the plant sets pods will encourage the plant to produce more shoots, diverting energy away from producing the edible bean pods.
Use sharp scissors or pruning shears to cut the main stem of the pole bean back to your desired height. Do not cut lower than any set pods. Cut back any portion of the plant that has grown taller than the support pole or trellis.
Cut off all side shoots that are not actively bearing bean pods as the season comes to an end in the fall. This encourages the plant to ripen the pods already set, providing you with one last mature harvest.