When is the best time to prune forsythias?
Forsythias bloom on the previous year’s growth. The best time to prune forsythias is immediately after flowering. Pruning forsythias anytime from mid-summer until just prior to bloom will reduce flowering in spring. When pruning mature forsythias, it’s best to remove one-fourth to one-third of the oldest (largest) stems at ground level every other year. New shoots will emerge from the ground and bloom in following years.
Old, neglected forsythias can be rejuvenated by pruning the shrubs back to within 4 to 6 inches of the ground in late winter or early spring. The shrubs will grow back quickly and should begin blooming again in 1 or 2 years.