[header] How to prune forsythia [title] Prune forsythia plants right after they finish blooming in the spring. [step] Wait for your yellow flowers to fade and for the leaves to grow. At this point, the plant starts to develop next year's buds, and the plant carries the buds through the fall and winter season. 
This is the best time to prune your forsythia. [substeps] Forsythia is a perennial plant, and this grouping grows the best if you prune the plants in the spring.