Forsythia bushes have a wonderful arching habit will makes them a great focal point when planted in a large garden bed. All shrubs need pruning, but what do you do when you have totally overgrown forsythia shrub? It’s either time for hard pruning or renovation pruning for them.If you stay on top of pruning forsythia bushes you will be able to keep them well under control. But a neglected shrub can grow to quite an immense size in both height and width.
Remember that the plant throws up many new canes each year, and what once started as a pretty 3 foot shrub will become an overgrown monster that takes over the whole garden space in just a few short years.
We all know forsythia as a perennial plant loved for its early yellow spring flowers and pretty arching growth habit. It is one of the earliest shrubs to flower in spring and can also be forced indoors very easily.
But an overgrown forsythia will get leggy, will lose the arching habit from having the branches lopped off mid length, and lack the luster of a well pruned shrub.
Sometimes the answer is to move the forsythia bush. See my tips for transplanting forsythia here. But often renovation pruning will do just fine.
When to trim forsythia
The best time for trimming most flowering shrubs is the in the spring, right after the plant blooms. If you wait until summer or fall, you will be cutting down on the number of spring flowers that you get next year. Forsythia blooms on old wood, so pruning too late will cut off the flower buds that formed earlier in the year. Annual pruning is a good idea to keep the shrub manageable in size. All good intentions aside, sometimes this just doesn’t happen and you end up with a huge shrub that has taken over.
My forsythia shrubs were a mass of yellow color this spring. Little did I know that my lack of pruning the last couple of years, while giving me great blooms, also gave me a plant that is pretty unruly this year!
The rule of thumb, when it comes to forsythias, of cutting about a third of the canes is only for yearly pruning where you plan to remove just a few of the branches. In the case of renovation pruning or hard pruning, other factors come into play.
What is the difference between renovation pruning and hard pruning?
Think of a house renovation. When you talk about renovating a house, you are doing perhaps one room at a time. It’s rare to take the whole house back to the studs and start over. The same idea goes for plants. Renovation pruning thins out a plant by leaving most of the plant but removing the oldest and weakest branches. It gives the plant a chance to grow new branches that are more healthy and vigorous. Hard pruning cuts the shrub right down to its base and allows it to regrow into a new shrub.
Renovation pruning of shrubs leaves you a better looking plant (temporarily,) which may still flower the flowing year. Hard pruning leaves an unsightly stub for a while and you’ll have to wait a couple of years for the plant to flower again. Also note that some plants can’t take hard pruning. (Red Bush is a good example of a plant that can easily be killed if its cut back too far – Ask my husband.)
Tools for renovation pruning and hard pruning
I used both bypass pruners and long handled tree pruners for my pruning job. None of my forsythia canes were much larger than about 1 1/4 inch in size so these two tools did the job well. I used the long handled pruners for the larger canes and the bypass prunes for the smaller branches that were unhealthy looking or took up too much center space. The long handled tools give more leverage and make the job of cutting the thicker branches much easier. They also gave me a cleaner cut.
Renovation Pruning of Forsythia
I have forsythia bushes that grow along one side of my garden. They all started from one plant which got dug up and divided into 7 individual shrubs. That was four years ago. They are so large now, that the chain link fence is totally hidden (good) but the plants in front of the forsythia are getting lost.
The shrubs are not so overgrown that they need to be chopped right now to the ground. But they really do need to be resized so that they fit better into the garden bed where they are planted. It’s time to get out the tree loppers and get this line of forsythia bushes into a smaller size.
Most of the shrubs still have quite a nice shape, but are just too large for the location and dwarf the other plants growing nearby. The branches are growing into the fence and need more than a light pruning, but not so much as to change the overall shape. It’s time for some selective renovation pruning to change the look of this shrub into a more tidy one and smaller one.
There are a few steps to take when you try renovation pruning on forsythia shrubs. First, remove 1/3 of the canes as low to the base as you can get. Once a forsythia is quite a mature size (as in like mine), this should be done each year. The oldest branches will produce less and less flowers over time, so they are the ones to remove. It’s easy to tell which ones they are, since they have the largest diameter and often have spit tips that can get pretty mangled looking.
The arching habit of the forsythia bush may be lovely to look at but it sure isn’t lovely when you decide to prune the plant. How on earth do you get close enough to the inside of the shrub to remove them? Forsythia are such leafy shrubs that it is very difficult to see into the center to decide what to cut back, unless you prune in the winter when the leaves are gone.
My answer was to use car roof tie down ratchet straps to tie up the whole bush so that I could see the base. It was then easy to figure out which branches to remove without poking my eyes out. I cut the oldest and thickest canes while the plant was tied up and then removed the straps so that I could thin to get the shape I wanted.
The ties also showed me just how many baby forsythias were growing around the base of the plant. No wonder the shrub looked so large! At least now I can see what I am taking out for canes.
A well groomed forsythia plant should look like a large vase that holds long arching feathers. That is its natural shape. Trying to trim it into a ball or a hedge is going to give you a season of more and more trimming, as well as reducing the number of flowers you’ll get next spring. Go with nature, not against it!
Don’t worry too much about exactly which canes to remove. I just look for the thickest ones. The idea is to reduce the size of the plant , not to worry too much at this stage about the shape of it. The plant will take care of that in time.
After the oldest canes have been removed, examine the shrub. Just have a look for other canes that seem weak, dead and unhealthy and for those that cross over the middle of the bush, ruining the shape of the shrub. Thinning them out will give you a better looking and more healthy plant. Remember that since forsythia blooms on old wood, removing a lot of the old canes will likely mean that you won’t get as many flowers next year.
Also, look for those canes that have been “headed” with a split tip. These branches have more leaves and side branches than a traditional forsythia cone and interrupt the look of the shape. Follow those back to the base and remove them. They are always the ugliest branches and usually the thickest one.
Other branches to look for to remove are those that are very low and growing close to the ground. They will eventually tip root, so get rid of them. Think of a vase of flowers. That is sort of what you want as the base of your plant with the branches spilling out the top.
Be sure to cut at least a few canes from the center of the plant. This will give room for new healthy growth and will also allow sunlight to reach into the center of the plant so that you will get new growth from the base and not just side shoots from the longer branches (which is what gives it a mangy look as it ages.)
A good rule of thumb for renovation pruning is to remove about 1/4 to 1/3 of the oldest and weakest canes. If the plant is really overgrown, like mine were, you can remove about half of them. Renovation pruning can be done in either spring (best, in my opinion) or fall. I advise against it in summer, since pruning is stressful on a plant and you don’t need drought situations added to the mix. The picture below shows the shrub after pruning it down quite a bit. So much prettier looking than my overgrown mess!
The finished shrub will have a much better size and will still have a similar shape, although it won’t be as full. Since it is early in the year, the additional growth will fill in but the branches will be much more healthy and lush looking with no damaged canes. A few less flowers next year, perhaps, but this is a small price to pay for a much smaller shrub that will allow the other plants in the garden to shine too!
When do you hard prune forsythia?
The best time to hard prune forsythia is when the plant has become so over grown that normal pruning won’t do much and the branches are starting to have sparse areas where no leaves grow and they look mangled. Another time is when the plant is just taking over the area in the garden where you have it planted.
I had one forsythia bush that needed to be cut right back and it’s sending up new growth in just a few weeks. It had been taken over by a honeysuckle vine that was growing all through it. I couldn’t get into the center to find out what growth belonged to which plant, so I hard pruned it fairly close to the ground. The whole left side of the forsythia was a tangled mess of honeysuckle!
I just cut it down to about 18″ from the ground trying to leave some of the new growth that had already started. It’s still early spring so it won’t suffer from extra heat and I can get rid of the honeysuckle at the same time that was growing along the fence top.
I will watch this one and shape it as it grows to make sure I get the shape I want. It looks a bit odd in the center of my long row, but it had so many mangled canes and vine overgrowth that it really needed a buzz cut! I would normally wait until fall with hard pruning, but the plant is part of the line of shrubs along the fence, so it got done now.
Hard pruning forsythia is normally best done in late fall. It won’t flower next year anyway and pruning it then will allow you to enjoy the look of the plant as it grows during the summer and you won’t have the ugly stub staring at you when you are out and about in the garden. It will also give the plant an extra month of growth. You WILL lose the flowers the following spring but you’ll still get the lush new growth of leaves. The growth rate of forsythia is very fast, so you won’t have that ugly clump for long.
Cutting back forsythia bushes is actually easier to do than renovation pruning. You just cut all the canes close to the ground. When the plant starts growing again, you’ll get new branches that are more healthy.
New canes will look quite different from the old mature ones. The new shoots are thin and very straight and grow very quickly. They have few flowers and long spaces along the length. Eventually they will begin to arch and put on some side branches and flowers as they turn into replacement canes for the ones you have removed.
Note: Be careful with hard pruning. If your forsythia shrub is quite old, cutting it back this far may kill the plant. But since old and overgrown forsythia bushes look pretty awful and don’t flower well, that may not be a bad thing. Perhaps, it’s just time for a new one.
The good news is that the arching habit of forsythia is just what you need for new plants. The plant naturally tip roots. The weight of the branches dip down and touch the ground and then the tips will root and begin a new shrub. I had some good sized ones around the base of each of my plants that were well established.
A mature forsythia, untended for a few years might look like one plant but actually be 8 or more! I had two or three around most of my shrubs. Left untended, these extra plants can take over a whole bed, which is one of the reason my other plants were being dwarfed!
However, they were easy to dig up and I got a whole batch of plants for free. Transplanting forsythia offsets is very easy and they take very well. I intend to plant them on two sides of a stairway of a backyard garden storage shed, as well as along the back fence of our large back lawn.
I had 7 overgrown forsythia shrubs that needed renovation pruning. As I pruned them down the fence line, I just pulled up the baby plants growing nearby and stuck them in a bucket of water. When I was done, I had at least a dozen more plants, and about 5 pretty good sized shrubs that just need digging up and transplanting somewhere else in the yard. They tip root in a ridiculously easy way. Looks like my gardening buddies will be getting a new plant!
Mistakes people make when pruning forsythia bushes
- Worrying too much about which canes to choose. Forsythia is a very forgiving plant. You really can’t go wrong just by remove the oldest mangiest looking, thickest canes.
- Not taking the size of a mature plant into consideration. Forsythias will be a big plant. Trying to tame it forever is a losing proposition. Plant it with room to grow or you’ll always be stressing about getting it to the right size.
- Pruning at the wrong time. Remember that the blooms grow on old wood. Early spring is best for most pruning other than very hard pruning.
- Cutting off too many canes. I get it. It’s hard to see the canes let along get into the plant to start removing them. But don’t just cut the whole shrub to the ground unless it really needs it. It can kill a plant that is not as established just as easily as a really old one. Selective pruning is often best.
- Not understanding the natural shape of the plant. A forsythia should look like a vase with cascading flowers. Trying to turn it into a hedge or a finely pruned topiary just won’t work well. It will look ugly and won’t flower much.
A word on the size of forsythia shrubs
When you walk into a nursery and come out with a forsythia plant, it will be just a tiny fraction of it’s mature size. Forsythia shrubs will easily grow to 10 feet tall and just about as wide. (Mine were at least 6 by 6 feet in just four years!) Keep the mature size in mind when you are planting and give the shrub plenty of room around it to grow. Then you won’t have to worry so much about the plant taking over a garden bed.
This overgrown forsythia might look pretty big but in the world of huge forsythia bushes, it’s just a baby! Give it a few years more of this neglect and you won’t be able to get near it!
All babies eventually grow up. Baby forsythias won’t stay small for long. When they are all grown up and adult, they look best in the middle of a lawn or large garden bed, where they can arch out to their hearts content. (But watch for those tip roots, or you will have a whole yard full of the plant!)
Forsythia Shrubs after Renovation Pruning
Once I realized how overgrown my forsythia shrubs had gotten, I gave them all a very heavy renovation pruning. Not a hard prune all the way down, since it is spring and I don’t want to see stumps along the fence line, but a significant prune just the same. I can see into my neighbor’s yard now, but the bushes are much less mangled and overgrown. I am missing the way they covered the metal fence but it won’t be long before that is the case again. Forsythia bushes grow quickly.
It is almost as though I planted new shrubs. I can’t believe the overgrown mess that I had here a few days ago is so tidy and small looking now!
Forsythia are quite forgiving plants. Try to spend a few minutes renovating them each spring by removing older canes and you won’t have to go to the more drastic effort of hard pruning and starting over to get a new plant.