Pruning Forsythia – How to Prune Forsythia

Last Updated on March 18, 2021 by Grow with Bovees

Regarded as nature’s spring weed alert, there’s truly a lot to love about forsythia! A member of the Oleaceae or Olive family, forsythia blooms for several weeks before it reaches peak bloom when soil temperatures warm up to 55-degrees F. Forsythia in bloom is a reliable sign that seeds of early weeds such as crabgrass are about to germinate.

This gives gardeners plenty of time to get their weed control gear together and apply pre-emergent herbicides at the correct time, or organic options such as gluten meal. Forsythia’s peak bloom time also happens to be exactly when crabgrass germinates, which is followed by other pesky lawn weeds at different times throughout the spring, summer, and fall.

Another reason forsythia is a favorite for many homeowners is that its bright yellow flowers are one of the first things to appear in early spring. Forsythia’s cheery yellow flowers make it a great addition to a home garden, or near a window, door or walkway.

Reasons to Prune Forsythia Shrubs

There are myriad different and some smaller species of forsythia, but most grow to about 10-feet to 12-feet tall and wide. If not pruned regularly, forsythia can become an overgrown mess, with suckers and straight branches stemming wildly in every possible direction.

Even though forsythia is regarded as a hardy shrub, and one that is able to tolerate almost any soil conditions, the shrub can get old or die if not provided with its basic growing needs. Speaking of which, a forsythia hedge may look dead when it stops blooming, but may just need a bit of TLC to rejuvenate.

overgrown forsythia branches with arching habit bearing yellow forsythia flowers

Pruning however is widely considered a daunting task in gardening but is well worth the effort. Adding to this, pruning forsythia is much easier than other shrubs, given that it grows fast, hence any errors are temporary, and can be fixed in subsequent years.  

Best Time For Pruning Forsythia Bushes

Renovation pruning of old forsythia is possibly the best way to revive the forsythia plant and should be completed before mid-July or when it gets really rangy-looking. Further, given that the flowers are its only ornamental trait, it is important to prune forsythia after it finishes blooming for next season’s optimal flowering potential.

Tools Required For Pruning Forsythia Plants

To prune forsythia properly, you need the right tools. Hand pruners aka pruning shears work well on a thin forsythia branch that measures up to a half-inch in diameter. Because they work similarly to scissors, pruning shears are a great tool to cut smaller branches. If you suffer from arthritis, then you should use the best garden tools for arthritis that are available.

These are ideal for the more tender branches;

If you have thicker branches, you can use a small pruning saw, anvil pruners, or long-handled loppers to cut the larger canes easily. Regardless of the tools you use, it is highly important to carry out the pruning job at the right time i.e. right after the shrub blooms, because late pruning will get rid of the flowers for next year.

forsythia bushes have a beautiful show of spring flowers
Forsythia flower buds will brighten up any garden bed

How to Trim Forsythia Bushes

There are several ways to prune forsythia, but the best way depends on the state it’s in, and gardener’s choice. If you have a healthy forsythia shrub, but it’s far too large, you can cut the whole shrub down close to the ground aka rejuvenation pruning.

Whacking forsythia all the way to the ground encourages new growth from the base, and is a recommended approach if the shrub serves as an important backdrop in your garden. You can perform total rejuvenation every three to four years to keep tabs on the shrub’s growth and to achieve a neat look for the forsythia bush.

Approach 1 to Pruning Forsythias

Another preferred approach is to cut the oldest forsythia stems at the ground level. Stems of forsythia tend to become thicker throughout the shrub’s period of growth, which can result in friction that can be detrimental to the plants’ health.

Identifying the older forsythia stems is easy, given that they are generally the tallest in the plant. You can use a handsaw or better yet a pair of pruning shears to cut the forsythia stems at roughly three to four inches above ground level. But it’s worth noting that this type of pruning is only great on forsythia shrubs that are at least five years old.

Approach 2 to Pruning Forsythias

Another way to prune forsythia that’s not as harsh as the first approach is cutting the older stems that are located at a 12-inch distance away from the bottom of the stem. Pruning forsythia at this distance leaves helps spur regrowth, and promotes the growth of new shoots.

show off the magnificent flower color on the branch tips

Approach 3 to Forsythia Pruning

Branches located towards the base of your forsythia shrub can affect its overall shape. Pruning these low-lying branches with a pruning shear or similar tool will help maintain forsythia shrub configuration, and replenish its appeal. But it is important to prune at the point where the branches emerge off the other stem.  

Approach 4 to Pruning Forsythia Bushes

For forsythia stems that are taller than average, you can prune them to roughly five inches in height. This pruning method is only advised if your forsythia is growing erratically, and during the last days of the winter. After pruning forsythia using this approach, remove the branches to give the shrub lots of room to spread as it grows. With all these pruning methods, remember to keep your tools clean, this can be done using hydrogen peroxide solution.

Final Thoughts

Pruning forsythia can be tricky but is a task that must be done to maintain the overall appeal and health of the shrub. Since forsythia can grow fairly large and wide, you should plant them far apart from each other, so that they have the essential space to grow, and bloom to a mature size. Forsythia roots are not generally known to be invasive, so they should be ok to plant quite close to homes or outbuildings.

Forsythia is one of the few shrubs that do not require much maintenance in order to grow. The only care it requires is timely pruning to encourage flowering in the springtime. Forsythia is a naturally deep-rooted shrub and does retain moisture well from below the soil surface.

If the forsythia is planted in poor soils, you can add organic fertilizer such as blood, fish, and bones in April and September to help improve the health of the finer roots located near the soil surface.

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