Pruning Forsythia — When to Prune Forsythia Bushes

Last Updated on March 11, 2022 by Grow with Bovees

Our very own ‘arrival of spring’ alert from Mother Nature!

There’s truly a lot to love about forsythia…

Not quite so appealing, unfortunately, is the fact that; the arrival of forsythia blooms is also a reliable sign that the seeds of early weeds, such as crabgrass, are about to germinate. But, for now, we’ll answer the often asked question when to prune forsythia?

Whichever way you look at it though, bright yellow flowers appearing on your forsythia shrubs, prompt a major call to action — away from the comfort of your winter armchair by the fire, and out into your yard!

Pruning is widely considered a daunting task in gardening, but its rewards are well worth the effort required.

Luckily, pruning forsythia plants is far less daunting than pruning a lot of other shrubs, because its rapid growth means that any errors caused by improper pruning, can usually be corrected in a single season.

careful pruning of orsythia will ensure an abundance of bright yellow flowers

A Bit of Background About Forsythia Bushes

An early flowering deciduous shrub, forsythia is a favorite for many homeowners because its bright yellow blossoms are one of the first things to appear in late winter or early spring.

A member of the Oleaceae or Olive family, forsythia has a blooming period of several weeks before it reaches peak bloom, when soil temperatures warm up to 55-degrees.

Forsythia is regarded as a hardy shrub, able to tolerate almost any soil conditions and, although it prefers full sun, it is also able to tolerate partial shade.

Forsythia’s cheery yellow flowers and arching habit make it a great addition to a home garden, or near a window, door or walkway.

Reasons for Pruning Forsythia Shrubs

Size

Although there are many different and some smaller forsythia varieties (some with a different flower color), the majority of those readily available can grow from 10 feet to 12 feet tall, AND a similar number of feet wide.

For this reason, if not pruned regularly, a mature forsythia plant can quickly outgrow its welcome and become an overgrown mess, with suckers and dead branches stemming wildly in every possible direction.

Sometimes a height of 10 feet is not a problem, but a width of 10 feet quite often is in an average sized yard. So ‘slimming’ your forsythia down a bit to suit the site or keeping your forsythia hedge within your property line, is often necessary.

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Health

Once the spectacular show of yellow flowers ends, forsythia bushes sometimes can ‘look’ a bit like they’re dead, when in fact it may just be in need of a bit of TLC to rejuvenate it.

Signs of potential health issues include split stems, the result of which can be a fungal disease, so if you spot any split stems then it’s best to cut them off straight away, no matter what time of year it is.

Also, stems of forsythia bushes tend to grow thicker as they get older, resulting in friction when they rub against each other.

This can be detrimental to the plants’ health, as it damages their protective layer, again risking infection..

 Aesthetics

Being a fast grower, a forsythia bush can quickly lose its shape and take more than it’s allotted ground in your garden bed, so it needs to be kept in check to maintain it’s show-stopper qualities AND stick to its own spot!

Forsythia flowers are the main attraction, so the more flowers you can get it to produce, the better, and appropriate trimming encourages more flowers.

Tools Required For Trimming Forsythia Shrubs

To trim any plant properly, as most reasonably keen gardeners know, you need the right tools.

Because they work similarly to scissors, pruning shears, aka hand pruners, are a great tool for cutting thin forsythia branches that measure up to a half-inch in diameter.

Because they work similarly to scissors, pruning shears, aka hand pruners, are a great tool for cutting thin forsythia branches that measure up to a half-inch in diameter. If you suffer from arthritis, then you should use the best garden tools for arthritis that are available.

Hand pruners are also ideal for taking forsythia cuttings.

Hedge shears are not suitable for anything but really spindly branches.

For cutting the thickest branches, you can use; a small pruning saw, anvil pruners or a pair of loppers.

Higher branches may require the use of a telescopic manual pole saw.

Forsythia Pruning Tips

There are several ways to prune forsythia, but which way is best, depends on; the state the forsythia is in, the gardener’s preferred method and the space available.

Hard Pruning Forsythia for Re-shaping

If you have a healthy forsythia shrub, but it’s just far too large, then you can cut the whole shrub down close to the ground, aka ‘rejuvenation pruning’ as briefly mentioned above.

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Whacking forsythia all the way down to the ground encourages new growth from the base.

This 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 a reign on the shrub’s growth habits and to achieve an overall neat look for your shrubs.

This basic approach for an unruly bush involves cutting the oldest woody stems down to ground level.

Identifying the older forsythia stems is easy, given that they are generally the tallest in the plant.

One can use a pair of pruning shears, or a handsaw if necessary, to cut the forsythia stems to roughly three or four inches from ground level.

Not only will this improve air circulation for the plant, but it will also allow better light penetration to the plants core, so that flowers can bloom in the interior as well as the exterior.

However, this hard core approach is only recommended on forsythias  that are at least five years old.

Less Drastic Annual Forsythia Pruning

A less harsh approach for the natural growth of younger bushes, is to prune the oldest stems at a 12-inch distance from the base of the stem.

If you have a restricted area for your forsythia then yearly trimming of branches is the best way to keep a check on wayward growth. It is also a great opportunity to take forsythia cuttings from the tips if you are a keen propagator.

Pruning forsythias at this level means one can create the basis of a nice shape without the bush having to start again from scratch, while at the same time, promoting the growth of new shoots and consequently new flower buds.

Pruning Forsythia Bushes With Straggling Growth

Straggly branches located towards the base of your forsythia shrub or sticking randomly out the top or sides can detrimentally affect the appeal of its overall shape.

Regular trimming of branches close to the ground & random renegades with a pair of pruning shears or similar tool will help complement the natural form of the shrub and replenish its appeal as well as promoting new growth.

Just remember to prune at the point where the branch emerges off the other stem.

 Best Time For Dramatic Pruning

If it reaches 12 or so feet tall, a good bit of ‘renovation pruning’ is probably the best way to give an overgrown forsythia bush a new lease of life.

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This should be completed before mid-July, or when it starts to get a bit rangy-looking, it’s certainly not safe to leave a drastic prune until late summer as you’ll risk lopping off the spring flowers that are in the process of forming.

Given that the yellow flowers are its only ornamental trait, it is important that one prunes an overgrown forsythia after it finishes blooming, for optimal flowering potential as early as late winter next season.

Regardless of the type of pruning, as I said, the most important thing is to carry out the renovation pruning job at the ideal time for new shoots to form. Late pruning at the wrong time will affect the flower buds forming for next year.

overgrown forsythia with arching habit bearing yellow forsythia blooms

Final Thoughts

Pruning forsythia is a bit of a chore, but it is a task that should be done to maintain the natural shape & health of the shrub.

Pruning will also ensure lots of flower buds form at the branch tips for the following season, to ensure a lovely display of yellow blooms.

Since forsythia can grow fairly large and wide, you should plant them reasonably 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. Weeping forsythia (Forsythia suspensa) in particular, looks beautiful trained along a boundary wall and bush varieties make beautiful formal hedges to screen you from your neighbour.

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.

The best time to prune forsythia is from late spring onwards, as soon as blooming is over, is really the only care it requires to ensure abundant flowering in the following late winter to early spring.