By Sarah Wilson
If you find out how to prune forsythia properly, it will make all the difference to how it looks. Despite its many virtues – fast growing, tough, easy-to-cultivate – forsythia seems to suffer from a major image problem. Some see it as old fashioned while others simply hate it. One of the reasons for this is the way it’s often hacked at during pruning, which can leave it looking much the worse.
As forsythia grows fast, reaching maturity in under a decade, wayward growth can leave it looking messy. This often leads to it being butchered with the shears. If planted in the wrong place it can rapidly outgrow the space and this leads to another bout of hacking to try to tame it. But being vigorous by nature, it will simply respond by growing even more enthusiastically.
If your forsythia is correctly pruned it can be a real asset to the garden. Flowering in early spring they bring the garden alive with a burst of sunshiny yellow. The key thing to remember is to prune it after your shrub has finished flowering. Once the flowers are over the plant steps out of the limelight until the following spring when those golden yellow flowers appear once more to add their unique splash of colour.
Read on to find out how to prune your forsythia to give it some TLC, plus check out our guide to pruning shrubs for more top tips on keeping your garden looking its best.
How to care for forsythia
Before we get round to the business of how to prune forsythia, there are one or two points to take into consideration. First off, are they in the right spot? Give them plenty of space, and plant them in the right place where their rapid growth won’t be a problem. With maturity reached so quickly getting the right pruning regime in place is vital, and fortunately it’s really straightforward.
Forsythia are vigorous shrubs. Once established all they need is the correct pruning to encourage flowering in spring time. They are naturally deep rooted and will search out moisture well below the soil surface.
Feed in spring and autumn with some garden compost or well rotted manure to help establish a good root system. Then keep the area around them free from weeds. You can find out how to compost in our expert guide.
How to prune forsythia: pruning an established forsythia
If you inherit a very overgrown forsythia bush that’s not in the best shape and needs smartening up, the best plan is to chop it back completely to a height of around 1 metre once the flowers fade. It will produce very few flowers the next year but will soon recover by the year after. Although an established forsythia can be hard pruned virtually to the ground, if you want to maximise flowering it's best to remember to prune them once a year.
How to prune forsythia: pruning a new forsythia
This one is easy. For the first two to three years after planting a new forsythia don’t prune it. This lets the bush develop into an attractive natural shape and helps establish a good root system.
When your shrub is three or four years old it’s time to start pruning it. The timing is easy – always do it after flowering. It’s important to prune then as forsythia flower on shoots grown the year before flowering, so if you prune too late you’ll be removing the flowers for next year. Shape by removing about a quarter of the length from all stems.
Every other year, prune about a quarter of all stems back to ground level from the centre of the bush. When doing the above keep an eye out for damaged stems. Trim these first, then move on to dealing with any stems which are crossing over each other.
After five or six years it’s a good idea to remove about 20-30% of the oldest stems completely, right down hard to the ground. This will stop the bush from becoming congested and improve air circulation, reducing the risk of disease.
Do forsythia make a good hedge?
Forsythia is a popular choice for hedges, but it doesn’t make a neat hedge because it goes against its natural form of growth. Unlike smarter yew, beech and privet hedges, it looks unkempt between trims. It doesn't look right as a 'natural' edge either as its too dense. Plus those vivid yellow flowers can somehow look odd seen against the rigid geometry of a hedge.
There's more ideas for garden boundaries in our guide to the best fast growing hedges.
When and how to plant liatris bulbs: expert advice to get it right
Plants Find out how to plant liatris bulbs and you can add height to your borders with this easy-to-grow plant
By Anna Cottrell •
Cheap no-grass backyard ideas: 10 low-maintenance looks for your space
Ideas These cheap no-grass backyard ideas prove that you don't need turf to transform your garden on a budget
By Holly Crossley •