Start the pruning process early. Cut young plants back to the top 2 leaves. This encourages the basil plant to form new branches and new leaves.
Remove flower buds immediately. Pinch them off before they reach maturity. If the flowers are allowed to fully bloom, the branch bearing the blossoms will slow production of leaves and reduce the harvest. For bushy basil plants, look deep within the plant for flower buds.
Shape the basil plant. As the basil plant grows larger, cut it back so it does not crowd its neighbors. Prune from the top at the intersection of 2 branches. The basil plant will generate new branches in that area. Cut the side branches as well. Basil likes air circulation.
Be assertive. When a basil plant approaches full maturity, at about 3 months, do not be afraid to cut it back by one-third. This stimulates the plant and its production of new leaf growth.
Prune often. At full maturity, a basil plant may need to be pruned once every 2 weeks or as much as several times a week. This depends on the variety of basil plant and the growing conditions.