Forsythia Rejuvenation Pruning: Tips On Hard Pruning Forsythia Bushes

Large Forsythia Bush In Yard
overgrown forsythia
(Image credit: Gardening Know How, via Nikki Tilley)

You probably have an old forsythia, or know someone that does, in the landscape. While these start out as attractive landscape shrubs, over time they can lose their luster. Keep reading to learn more about hard pruning forsythia bushes once they’ve outgrown their space.

Rejuvenating Old Forsythia Shrubs

Forsythia shrubs are known for their excellent display of bright yellow flowers in late winter or early spring. These fountain shaped shrubs originated in Korea and China. They are deciduous and typically stand 6 to 10 feet (2-3 m.) tall. There are a couple dozen cultivars that come in a variety of sizes as well as leaf and flower color. Forsythias are great for screening out unsightly views and are excellent in the back of a mixed border planting. All that being said, forsythias look best with annual pruning maintenance. Like many large flowering shrubs, they can grow leggy, woody, and rangy over time. It is important to know how to rejuvenate forsythias so you can bring back their attractive natural form and encourage more robust flowering.

When and How to Rejuvenate a Forsythia

One form of forsythia rejuvenation pruning is to remove one-third of all the branches at their base. Some people suggest you do this regularly once the shrub is mature. Remove the oldest branches, as they produce fewer flowers over time. You can also remove any branches that cross over the others or look weak and unhealthy. This type of rejuvenation, which is called thinning, will encourage new branches to form. Thin your forsythia in late fall or early spring before the flowers form. Since forsythias bloom on old wood (stems that formed the previous summer), you’ll still have the remaining branches for flower display. New branches will have to be thinned if you get too many. Keep the healthiest looking ones. They will bloom their second year. If you are wondering when to hard prune forsythias, the best answer is when the shrub gets really rangy looking, is overgrowing its space, or has dramatically reduced flowering due to old age. Hard pruning forsythias is best done in late fall. It is actually an easy technique. You simply cut all the branches to the ground. A whole new set of branches will emerge the following spring. Once they have grown in, select the best branches to keep. You will once again have a fresh-looking, young plant with more productive flowering. Please note that hard pruning forsythia shrubs will cause you to lose one season of blossoms. Remember, they bloom on old wood. Another caveat is that if your forsythia is really old or otherwise unhealthy, it may not respond to hard pruning rejuvenation. It may die. So, there is a bit of risk with forsythia rejuvenation pruning. You can rejuvenate your forsythia every three to five years. Forsythia plants are happy plants. They tell us spring is here or at least just around the corner. Take care of them and they will bring you years of springtime happiness.

Karen Boness

Karen Boness is the founder of Wild Willow Design, an Australia-based company that specializes in ecological landscape design.