Pruning strategy for forsythia

– Posted in: Forsythia, How-to, Plant info
24 comments

Sparsely blooming 'Meadowlark' forsythiaRemember the forsythia I pruned so that I could force some branches? It doesn’t look so floriferous out in the open, does it? (For comparison, check out the forsythias here.)

When I’m faced with a plant that’s not doing as well as expected, I try to analyze the situation before taking action. In the case of the forsythia, I observed that the flowers were only on the ends of the branches. If it were cold damage, I would expect the flowers below the snowline to bloom, and the ones exposed to the cold higher up on the shrub to be missing. That’s not the case, and besides, this variety of forsythia is supposed to be bud-hardy to 30 below zero Fahrenheit, and it didn’t get that cold this winter.

I know that most flowering shrubs need lots of sun to give them the energy to form flowers, and I think this is getting closer to the problem. At first, I thought the lilac bushes on either side were shading the forsythia too much, but that doesn’t quite fit with the blooming pattern. All the missing flowers are towards the center of the shrub. I’m coming to the conclusion that the forsythia is shading itself too much, and needs a substantial thinning.

So in a week, two at the most, I’ll use my loppers to prune the thickest branches as close to ground level as I can manage. I hope this will let more light into the center of the shrub, enabling it to produce more flower buds for next year. If that doesn’t help, I’ll have to suspect the general root competition from those lilacs. If that’s the problem, the choices are:

  1. Remove one or more lilacs
  2. Relocate or get rid of the forsythia
  3. Make an effort to give the forsythia more water and perhaps fertilize it
  4. Reconcile myself to a less than optimum display

Given those choices, I will probably go with number 4. I don’t want to get rid of any of the shrubs (they do their job of screening us from the road quite well), and anything I do to help the forsythia in terms of extra water will no doubt help the lilacs just as much. The point of the forsythia is to give me pleasure in spring, and it does that, even without a maximum amount of bloom. I find that bright yellow immensely cheering. I need it; I want it; I’m gonna have it–but I know I don’t have time to baby it. For me, that’s an acceptable trade-off.

A Reader’s Forsythia

Recently, a reader commented:

We just bought a house and the forsythia is very overgrown and old. It has many branches deep inside the bush that have nothing at all on them. Do we try to cut out all those old, non-blooming branches and hope for the best? We love forsythia. Help!!!!

This sounds like the same problem my shrub is having, only to a much greater degree. If a branch truly has nothing on it–no flower buds and no leaf buds, either–the branch is dead. By all means, prune it out. For branches that have leaves, but no flowers, the first step is to look around the shrub. Are other trees or shrubs shading the forsythia in summer? If so, no amount of forsythia pruning will help. You’ll have to prune away whatever is shading the forsythia, and that might not be worth the ugliness that might ensue.

You also have to consider if the forsythia isn’t bud-hardy for the climate. Any forsythia in the warmer part of zone 5 and south of that should be fine.

If both the above conditions don’t seem to be the problem, it does sound like a radical pruning is in order. Forsythias are very vigorous shrubs, and many people would advocate cutting the whole thing to the ground, watering and fertilizing well (using fertilizer suitable for flowering shrubs), and letting the shrub rejuvenate itself.

That’s just a little too scary for me. A more conservative approach is to cut out one-third of the branches for each of three years, gradually bringing the shrub into a more productive growth habit.

A “new” garden needs patient observation

When you first move into a house, you’re all excited and you want to roll up your sleeves and whip everything into shape. But really, the best thing to do is to wait a year and observe your property through the four seasons, taking lots of notes. For my first spring at this place, if I had assumed that the foliage coming out of the garden beds was old tired tulips that were no longer able to bloom, and had dug them out immediately, I never would have seen the colchicum blossoms that fall, and discovered a plant that has fascinated me for years since. Having said that, I can’t see how it would hurt to thin out your forsythia by pruning it this spring. Just watch where you step, there could be another plant growing at its base!

What discoveries have other gardeners made when they first moved into an established yard and garden?

About the Author

Kathy Purdy is a colchicum evangelist, converting unsuspecting gardeners into colchicophiles. She would be delighted to speak to your group about colchicums or other gardening topics. Kathy’s been writing since 4th grade, gardening since high school, and blogging since 2002.

If winter is slumber and spring is birth, and summer is life, then autumn rounds out to be reflection. It’s a time of year when the leaves are down and the harvest is in and the perennials are gone. Mother Earth just closed up the drapes on another year and it’s time to reflect on what’s come before.

~Mitchell Burgess in Northern Exposure

Comments on this entry are closed.

Linda Dolson May 22, 2014, 10:37 am

Forsythia in for 10yrs. the only blooms it ever got was at the very bottom on a couple of very small branches. I could have counted booms on one hand, so disappointed . It is in full sun and I do trim at proper time of year. Can you help me?

Kathy Purdy May 22, 2014, 1:41 pm

Linda, you don’t say where your garden is, so I am going to assume it is in a cold climate. The most commonly sold forsythias are root-hardy to Zone 4, but only bud-hardy to Zone 5–or even warmer, depending on the variety. What happens is the shrub stays alive, but only the flower buds protected by snow cover survive to bloom. The other cause of failure to bloom (besides improper pruning, which is not your problem) is lack of sun. If your forsythia is not getting shaded, then it is probably an old variety that isn’t bud hardy in your climate. If you really want a blooming forsythia, seek out a variety that is bud-hardy in colder climates. ‘Meadowlark’ is the most common, I think, but there are others.

Barb May 24, 2013, 2:16 am

Hello,
We have lived in this house for 3 years, our forsythia (that is planted in the sunniest area in the yard with nothing growing around it that would block the sun) had a few blooms the first year with short, dead looking branches. Second year, even less blooms and no new branches. This year, more branches, no blooms, only suckers at the bottom. The leave buds started to grow then just stopped. This is where we are now 🙂
I’m thinking I should just prune it down , just about a foot above the suckers.
Thoughts?
Thanks for your help!

Kathy Purdy May 24, 2013, 8:09 am

I would certainly cut off everything that is dead. It does not sound like it is thriving. My guess is the soil is very poor or very wet. Either that, or something is eating at the roots. You don’t mention the weather when you say the leaf buds started to grow and then just stopped. If you got hit by a hard frost then, it could kill the leaf buds. Then it would have to make new leaves, which would take time. The best thing to do is have an experienced gardener friend come over and take a look. The suckers are what you want to save, it sounds like. Forsythia always sucker and they will form flower buds the second year.

Laura March 30, 2013, 1:31 pm

We and our forsythia endured hurricane sandy. The forsythia started to bud, but the buds are brown and dried out. If I pinch a bud it crumbles in my hand. We live very close to the ocean, the hedge is at least 15 years old, it’s still early spring but I’m afraid the whole thing got wiped out by the salt water.
HELP!!!!! Is there anything I can do?

Kathy Purdy March 30, 2013, 4:42 pm

Even if all the branches were killed by salt water, I doubt the roots have been. Wait and see is what I advise. You may only see growth coming out from the ground. If you see no growth at all in another month, I would consult with your local cooperative extension or independent (ie, not big box) garden center. If it is really killed all the way down to the roots, forsythia is not an expensive shrub to replace, and you may decide to replace it with something else.

Jane K April 12, 2011, 6:04 pm

Jenny, thank you for your input – but what I was trying to determine is how far should I trim back the forsythia or should I let them go for the first year and then severely cut them back (to the ground or 5 inches or a foot) fro the ground so that I get nice thick bushes. As I said, I plan to keep them trimmed to about four foot high. I’m just not sure what to do the make sure the plants fill in nicely. Any suggestions. Thanks, Jane

Jenny April 11, 2011, 2:26 pm

I planted forsythia about 11 years ago (plants were about a foot high at the time) and I planted them 5 feet apart. If I did not trim them at all I believe they would be too tightly together. Before last year I use to trim them 2 or 3 times per season because I like the manicured look. Last year I cut them back to about 2 feet high and let them grow all season. This year I will be getting blossoms again. So I think you should plant them at least 6 feet apart.

Jane K April 10, 2011, 8:22 pm

Can you tell me how to start with new forsythia? I just planted 30 bushes and they are all about 2-3ft tall and I want to make a hedge out of them but want them to get get full and am not sure when or how far to cut them back to make sure they will mature into a nice full hedge. I love the bright yellow spring flowers. Can you give me your advice. Much appreciated, Jane

Andrea DuPree May 19, 2010, 8:11 pm

This year the forsythia did not bloom and is leafing out. The branches I tried to force did not bloom either! In the past, I have had success with this shrub. What do you suggest? Thanks!

Kathy Purdy May 19, 2010, 8:21 pm

You don’t say where you live. Was it colder this past winter than it usually is? When did you prune last year? If you pruned too late, it’s possible you cut off all the flowering branches.

Mark March 29, 2010, 6:34 pm

HELP….I’ve pruned … early…and late, I’ve not pruned…..even cut it back till it was barely a foot tall. I’ve fed it and…not fed it, and my Forsythia still has very very few bloom. Durring the summer months it has always grown lush and green and so full, but just never has any bloom on it.

Kathy Purdy March 29, 2010, 6:41 pm

Does it get enough sun? If it is shaded it won’t have enough energy to make flowers. Also, how cold is it in winter? Most forsythia flowers can’t take as much winter cold as the wood can.

don coffman July 14, 2008, 10:45 pm

i have a forsythia bush along the back side of my yard which normally is beautiful. it is better than a privacy fence. we have let it grow to about 9 feet tall, we keep it pruned on both sides to about 4 or 5 feet thick. the bushes were started from twigs and are about 20 years old. this year though they seem to be dying out in sections, i trimmed the dead out but cannot figure out what the problem is. we have had alot of rain so far this year, could this be a mold or mildew problem, and if so what can i do .

Kathy Purdy July 11, 2007, 10:11 am

Jenny, here is a good tutorial on pruning forsythia:
http://www.plantamnesty.org/pruning_topics/pt_forsythias.htm

Kathy Purdy July 10, 2007, 7:12 pm

Jenny, the standard advice is that you should prune no later than two weeks after blooming has ended–and then quit. How you prune is just as important. You should follow a branch that you want to remove all the way back to where it connects to the main branch and cut it there. Don’t cut the tips of all the branches (which is called shearing); each branch will divide where it is cut and give the shrub a frizzy look.

If you prune later in the year than 2 weeks after bloom is done and still get good blooming the next year, I guess you’re the exception that proves the rule, or you really aren’t taking much off in those later prunings.

Jenny Palmer July 7, 2007, 7:48 am

I prune after flowering and usually twice more in the year because I want the forsythia to look neat and tidy. Some of them come back with many blooms the next year while others do not. What is the latest time I should prune these to ensure flowers in the spring ?

Kathy Purdy May 9, 2007, 1:45 pm

Thanks for the advice everybody. I will probably tackle the job over the weekend.

DWPittelli May 4, 2007, 9:03 am

Forsythia will almost always survive being cut back to the ground in spring — if you water it in dry, sunny weather. As noted, you can also cut out 1/3 or 1/4 of the oldest branches to the ground every year, with almost no risk. But that will take 3 or 4 years to get a “finished” bush.

You can average these two methods. To have a larger bush next year, and reduce any risk of sudden death from a full coppicing, cut out perhaps 2/3 or 3/4 of the branches to the ground, right now. By all means, fertilize some (I’d go with a Plant-Tone or Holly-Tone at half recommended dosage), and water as needed. There will be almost no risk of plant death, and you will have a significant bush next year, with improved flowering.

Then next year, after flowering, and in subsequent years, cut 1/3 or 1/4 of the oldest branches to the ground, as is generally suggested for long-run maintenance.

Mary Ann April 30, 2007, 10:46 pm

Well, let me jump right into this discussion. As Ki mentioned, you can prune back one fourth of the plant. I have taken more drastic measures and cut back at least a third. Even if you cut it all the way back to the ground, it will come back. We can’t get ours out of the ground without a back hoe, so we just cut it off to see what would happen. It’s back and happy and strappy and each branch was covered with blossoms.

It looks to me, from your photo, that you plants would benefit from a thorough pruning. Take out the tallest and the fattest branches, at least one third of them. Eyeball it, re-shape a bit, and forget it until next year. Then repeat in 2008. And 2009.

Carol April 27, 2007, 10:04 pm

I admire your analytical, systematic approach to determining why your forsythia didn’t bloom as well as in past years. I would guess that pruning out the oldest branches will rejuvenate it a bit.

Ki April 27, 2007, 8:40 pm

Hi Kathy, here’s some information about why your forsythias are not blooming well from thegardenhelper.com website.

“Pruning Forsythias

Forsythia flowers form on the previous season’s growth, not on new growth, so pruning should be done immediately after the flowers have faded. Once your Forsythia finishes blooming, take a close look to see what pruning needs to be done. Each year, you should prune back about one fourth of the oldest stems to within 4 inches of the ground.
If your Forsythia is drastically overgrown from years of neglect, it may stop blooming altogether. If this is the case, you can cut the entire plant to the ground. It may take a few years before you’ll see blooms again, but your shrub will come back, better than ever!”

I got tired of fighting our overgrown monster and finally dug it out which also did not bloom well because I pruned it at the wrong time. Now, I just enjoy other people’s forsythia.

Rundy April 27, 2007, 4:32 pm

I’m no expert on forsythia, but taking an educated guess based on what I’ve seen of other forsythia in my driving around this spring I think there may be one other possibility. You may have let the forsythia grow too stringy and spread out. It seems a lot of the more heavily flowering forsythia are pruned back to a more cohesive branch cluster. So, you may not have to thin the branches so much as trim them all back to a more solid hedge.