Pruning Forsythia - Tips For Trimming Forsythia Bushes

Gardener Trimming Forsythis Bush
forsythia pruning
(Image credit: Zbynek Pospisil)

After a cold, dreary winter, the sight of those bright yellow flowers along the branches of a forsythia bush will put a smile on any gardener's face. It is one of the first signs that spring has finally arrived. As the blooms begin to fade, three questions arise -- when to prune a forsythia? How to prune a forsythia, and will just trimming forsythia be enough?

Things to Consider When Forsythia Pruning

Since these durable shrubs need little care in the way of soil and nutrients, forsythia pruning is a chore that can easily be done annually. With diligent trimming, forsythia can be kept from the overgrown sprawl that is a common complaint. Young plants may only need a modest trimming. 

Forsythia that has been untended for years may need to be lopped to the ground. Forsythias are fast growing shrubs that can grow up to 10 feet (3 m.) tall and just as wide. Pruning forsythia is essential to control this growth. Trimming a forsythia while it's young will help control their shape and size.

When to Prune Forsythia

The best time for trimming forsythia is in the spring after the blooms fade. Pruning forsythia in late summer or fall will reduce the number of flowers in the spring since these shrubs bloom on old wood and set their flower buds soon after new growth appears.

How to Trim Forsythias

There are a few things to remember before you begin pruning. Forsythia has a natural arching habit in an irregular rounded shape and forsythia pruning should allow for this natural growth. Pruning forsythia into a formal hedge will remove most of the shrub's flowering potential. 

In a mature forsythia shrub, cut at least one-fourth to one-third of the oldest, thickest branches close to the ground. For the very oldest and most overgrown forsythia, pruning should be brutal, cropping the entire shrub to about 4 inches (10 cm.) from the ground. New shoots will emerge and, with careful trimming, forsythia can be renewed and rejuvenated. Within two years, you'll have a new shrub. 

Younger forsythia shrubs are easier to maintain with regular care. Take out the oldest branches to make room for new shoots. This also allows more light into the center of the forsythia. Trimming back any straggling growth will go a long way in neatening the look of your shrub. Spend just a few minutes each spring on forsythia pruning and your reward will be many years of spring-is-here smiles.

Jackie Rhoades

Jackie Rhoades began writing for Gardening Know How in 2010.