A few years ago, when I went to grab the hose, I noticed a ton of branches had been torn off my lilac bush. I accused my poor husband of getting overzealous with the pruners. However, I soon discovered that the hack job was the work of a mother squirrel that was meticulously building her nest. She’d rip off a branch or two and then run to my chimney (that’s a whole other story). I was worried about the lilac coming back the following spring, but it has been flourishing. Lilac is among my favourite spring scents—when I work outside on my deck, I take deep breaths when they’re in bloom, as they sway in the breeze. When those fragrant blooms fade, it’s a good time for pruning lilacs. So I thought I’d share a few tips!
The perfect time to prune a lilac bush is after the flowers have bloomed and faded. Spring-blooming shrubs should be pruned right after they have bloomed. If you save the task for later in the season, you risk pruning off next year’s blooms (because next year’s flower buds form on the current year’s wood)—a mistake I made in the past with an unruly forsythia!
Tips for pruning lilacs
There are three maintenance tasks I need to cross off my lilac to-do list in the spring. I need to trim the dead blooms off, prune the shrubs, and cut out suckers that have popped up underneath. Most of the stems I’m dealing with are thin enough that I can use my hand pruners, but if stems are thicker, you may want to use a pair of bypass loppers. Make sure the blades are clean before you cut. And while the plant is blooming, use the same sharp pruners to snip bouquets. You don’t want to tear or snap off blooms, as this could harm the lilac bush.
Trimming off lilac flowers
Removing the dead flowers from your lilac bush will encourage more blooms the following year. The important thing when trimming off your flowers is that you simply cut off the spent flowers—don’t worry about any surrounding stems. If you can see next year’s blooms forming (two new shoots coming from the stem), simply focus on the spent bloom’s stem. You don’t want to cut off next year’s flowers!
Now with my dwarf Bloomerang, I want to encourage a second blooming, which should take place towards the end of the summer or early fall. Pruning off the spent spring blooms will encourage more new growth and more blooms for that second bloom time. I could also add a light dose of fertilizer that’s been formulated for woody plants, which will also encourage the shrub to bloom again.
Pruning lilac shrubs
A good rule of thumb when pruning lilacs is not to prune more than one third of a shrub’s stems per year. When one of my lilacs climbed a little too high towards the eavestrough, I simply trimmed those branches to a reasonable height. I then trimmed the spent blooms and called it a day. You can also do a bit of light thinning to encourage new growth.
A more aggressive pruning, perhaps on older shrubs that haven’t been regularly maintained, should be done in late winter or early spring. At this point, you want to cut out older wood and malformed stems, and keep the newer stems to encourage new growth. Cut the older stems down to the ground.
With the Bloomerang lilac, I’ll just trim any especially long pieces to maintain the shape of the shrub. Bloomerangs have a nice rounded habit in the first place, so you don’t have to worry about shaping the bush too much. Mine has been in the garden for a few years and it’s still nice and small and compact.
Removing lilac suckers
Another part of pruning lilacs is removing the suckers. What are suckers? Around my lilac there are a few new lilac trees—single stems a few feet away, shooting up from the soil, making their presence known. These are the suckers. I simply cut them off at the soil line (or slightly below). However stems close to the trunk of the bush itself, you may want to leave, as a healthy lilac has a mix of old and new stems. You could also dig up the suckers and replant them elsewhere. Who doesn’t love new plants?
In a pruning mood? Here’s another piece I wrote about how to prune a rose of Sharon.
This video offers a synopsis of these lilac-pruning tips.
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Have you any suggestions for a lilac that loses its colour? I have inherited a lilac bush that bloomed prolifically this spring, but the blossoms quickly faded from purple to washed out cream. Is there something I can add to the soil to help it regain its colour?
Hi Julie, Have the blooms faded like that in previous years?
Tara, this has happened to our bushes as well….Very pale petals, and they hardly lasted 2 weeks (though it was very windy this past month!) I’m a big pruner, but misunderstood the lopping off the flowers when they’re done (I assumed they seeded for the next year)…so thank you for explaining that so well! Also, we do have quite a few suckers…I kinda like them for the green coverage (we have chickens who enjoy foraging with the protection) But I do thin the branches every year, and trim out the little, non-producing twigs so it doesn’t look so woody. A lot of our surrounding neighborhoods have big, even huge lilac bushes! It’s super obvious that none of these homes prune them… And their flowers are so vibrant, and so plentiful!! It’s been probably 3 years since we’ve had such blooms on our lilac… I do not fertilize at all, because of the chickens. And I don’t overwater, either… Our yard is a gorgeous oasis, And everything seems to grow super well for us! I’m just not sure why our lilac blooms have been so lackluster the past couple years… Thank you for any input! I really loved this article!
I have a lilac bush that is plentiful on one side and pretty open on the other side. It is about 8 years old and needs pruning. How should I proceed?
I’m guessing the open side isn’t blooming. A good rule of thumb when pruning lilacs is not to prune more than one third of a shrub’s stems per year.
A more aggressive pruning, perhaps on older shrubs that haven’t been regularly maintained, should be done in late winter or early spring. At this point, you want to cut out older wood and malformed stems, and keep the newer stems to encourage new growth. Cut the older stems down to the ground.
Perfect timing! Mine have just started to bloom and they are also getting too high.
Happy pruning!
Hi! I have a bloomerang lilac tree and I pruned it tonight. I think I may have pruned new buds by mistake (new Gardner here). Did I ruin the tree from forever blooming again?
No worries, Emily. If you pruned new buds off, new ones will grow back. 🙂
We are finally getting to relandscape my front yard and I have a lilac bush that is in need of trimming. Since it’s September should I wait until March or can I cut it back now. This year it did not bloom anyway due to being neglected for so long. If I cut it back now will it kill the whole plant? I’m not to concerned about gaining blooms right away, mostly just making it healthy again.
Hi Sara,
You can remove any dead or diseased wood now, but early spring is the best time of year to prune a lilac bush (if you’re not waiting until after it blooms).
Thank you for clearly stating how I should take care of my brand new lilac bush. I’ve checked several websites but no one was as clear and specific as you were, and I’m now sure I can *properly* care for one of my favorite flowers.
My 4 yr old bush branches cant support the blooms. Should I feed something in particular. It is @5 feet high and not dense at all
Hi Nanett, Mine drooped under the weight this year, too. Do you prune your lilac?
M lilac has to be more than 10 years old and I have blooms for the first time. May I cut the blooms and bring them into my house? Or should I leave them alone this year? Thank you.
We have a lilac tree which has bloomed on a few branches but the the other branches either have no leaves or flowers or withered leaves and flowers . Should we prune and if so how much. Can you give us some advice. Thanks
Hi James, Once the blooms have died, I would prune off anything that seems dead or diseased. The leaves curling could be powdery mildew. A little thinning, even of healthy branches, will help to ensure there is airflow through the shrub.
Hello,
New gardener, and new homeowner here. The previous owner has a gigantic lilac tree/bush (honestly its so big im unsure) it does flow over the roof top (one story ranch) and into neighbors driveway. I did not prune last year as i know basically nothing, and still learning tips and tricks. The neighbor said she has pruned her side for years and they are nice so i dont mind. The neighbor side bloomed beautifully this year. The side facing the yard, not so much. Majority (i would say over 50%) of the yard side seems to have no life. There are several bases to it. Over ten trunks from the ground. Is it safe to cut back all of the dead branches, or should i still stick to the 1/3 rule. Im afraid i will kill it and the previous owner is a family friend would not be so happy, nor would my neighbor who loves it, or me because I like it as well and would like to maintain it. Also i noticed on the yard side, the roots seem to be showing, should i add dirt as well?
Hi Crystal,
It’s okay to cut out any dead wood from the tree. This will also help with air flow. If roots are showing, I would cover them with fresh soil.
Hi Tara,
I am a new gardener. I got a house Last year. We have to lilac trees that bloomed this year. But not until the flowering I noticed the trees had a lot of dead wool and old blooms that were never pruned from last years. So, I pruned/cut back a lot of the dead wood that also had some new growing in them. I wish I read this before. That old lilacs might need to be pruned in a three year period of time. I did it all at once today. What does this mean to my two lilac trees? Did I ruined them forever?
Hi Daniela,
It’s okay to prune out the dead wood, and after they bloom is a good time to do it. I’d say your lilacs will probably be just fine.
I have one that is not blooming. Should I try pruning it back and seeing if it will bloom next season.
Hi Wendy, I would try pruning now to see if it encourages blooms next year.
We moved into a new house in August 2018 and have two lilac bushes on either side of the house in the backyard. One has produced about 4-5 branches of flowers so far but the other one has absolutely zero flowers. I noticed it didn’t really produce much of anything last year as well. Any helpful insight?
Hi Shannon, have you pruned your lilacs later in the summer?
I bought a Lilac bush 3 yrs ago, it is 5 feet tall right now but it never had flowers. I prune it before winter..does this the only thing wrong I am doing (what I learned from you) or any other thing also. What should I do now so it can bloom next year.
Hi Raaziah,
If you prune it before winter, it’s likely you’re pruning off next year’s flower buds. The best time to prune a lilac is right after it flowers, which is right about now.
Hello,
I had a 1 year old lilac plant that was doing great. I had it since it was about 3 inches tall. It grew to about a foot very healthy. I went out to look at it this morning and a squirrel tore it apart. there is still root about i inch down below the dirt. Is there any way I can get that to regrow?
Thanks
Hi Anthony, I’m sorry to hear that. I had a squirrel tear apart a mature lilac to build a nest in my chimney! It did grow back, but it sounds as though I had more left. That said, it is very possible that you’ll get some growth from that root that is still there. At the point, it’s kind of a wait and see scenario…
Hi Tara,
I have a dwarf lilac tree (I think). It was here when we moved her 6 1/ years ago. I’m trying to become a better Gardner and am wondering about pruning it. I may have waited too long. The tips are brown but when I look under the brown, it’s green. Also there is a gap in the middle of the tree on one side.
I would cut out the dead bits. If it’s recently bloomed, you can prune, but don’t wait until too late in the season as you’ll risk cutting off next year’s flowers.
Hi Tara,
I have a lilac tree that has green leaves with veins of white in them. Not sure what kind this lilac is. Any idea? Also it is early July and the blooms have been done for two and a half weeks now. Can I prune spent flowers still? Should I wait till spring now? Also seeing green like seeds on spent blooms, what is this?
Sounds like witches broom. Are the branches long with all the new growth bunched together at the top? If so, it is an incurable bacterial disease and needs to be removed before it spreads to surrounding plants.
Hi Carisa, I’m not sure what variety you have. You can still prune the flowers. The green seeds are the seed pods produced by the flowers. This is what you can trim.
Hi Tara,
I forgot to prune few lilac blushes I have.
they are probably 4 years.
It is summer, they look healthy, however when can prune them?
thank you!
Hi Talia,
The perfect time to prune a lilac bush is after the flowers have bloomed and faded. Spring-blooming shrubs should be pruned right after they have bloomed. If you save the task for later in the season, you risk pruning off next year’s blooms (because next year’s flower buds form on the current year’s wood)—a mistake I made in the past with an unruly forsythia!
Hi my Lilac tree has been very healthy until this year it seams to have been frozen. Our early chinook weather made it start to bud and then we got really cold weather. The tree now has some new growth and some branches go leaves. There are many that are dead. should I trim the whole tree back or just cut the dead branches off.
Advise.
Liat
Hi Liat, for this year, I would just focus on the dead branches and see what comes back next year.
I have a very old lilac tree. It was here when we moved in in ‘86. It is now to the point where the center woods are almost bare and the tree hasn’t bloomed nicely for the past few years. I had my husband take it down to the ground. I’m hopeful I haven’t killed it for good.
Hi I have a very tall lilac I decided to cut it down to about 6ft today did I make the wrong move and not have flowers in the spring?
Kind regards
Carl
Hi Carl, It’s possible that you may have removed some blooms, but anything below the six feet may have buds waiting for spring.
We have lived at our house for just over five years. I knew nothing about pruning my mature lilac bushes/trees. They have bloomed every year, except this year. There were a few buds starting but they never developed into blooms. So, the past couple of nights I have been using my hands to get all the dead flowers off from spring. I have seen several green buds so figured it was for next year. Well, I looked in the center and see several branches that have no free leaves on them. Does that mean they are dead and should be cut? I probably have over 30-40 stems coming up from the ground, or base of the tree. There are probably 3-4 trunks at the base that branch out and up. One Bush is fuller and taller than the other one. They both are at least 8-10 feet tall with the fuller bush almost touching the electrical line that runs to the house. I need to shape them, prune them, and cut them back so they look nicer and aren’t so wild. Also, I have lots of suckers all around the sides of the bushes and hanging over the driveway. I hope I didn’t mess these bushes up by taking off the dead, brittle flowers and the brittle dead branches. There are still a lot of branches that don’t have leaves on them period, just a branch with no stems or green sprouts for new growth. I want to make these trees healthier. These shrubs are probably 10-15 years old. Of course, that’s a guess. I know they are at least 8 based on pictures on the city’s website. Anyway, please, help me or direct me to some resources. I really don’t have much of a green thumb, so to speak. Thanks in advance!
Hi Jennifer, It sounds like you’ve done a good job of pruning. It’s okay to clip out the suckers, old blooms, and dead branches. If you’re looking for more care info, I would check with an arboretum or master gardener extension. Here’s one I found from Cornell. http://chemung.cce.cornell.edu/resources/lilacs
Hi Tara Nolan. I have a boomerang. Live 1 hour north of Toronto. It is 3yrs this summer. It is end of September and just noticed the level have brown on them. Almost all the leaves except for the ones near the bottom. It is almost like they were frost bitten. I looked under each leaf and they look healthy and green. Would you be able to explain this to me. Thank you for your time.
Hi Nadene,
We had a very hot, dry summer, so it’s possible that the plant has suffered a bit from the drought. It’s also possible it could be a disease, like powdery mildew or bacterial blight. I would search these and see if the leaf images compare to determine what’s affecting your plant.
Tara,
I am planning to plant several lilac shrubs toward the end of next month (October), before the ground freezes and I would like to have as long of flowering period as possible in the spring. My understanding is that different varieties bloom at different times, can you tell me what varieties are early, standard, and late bloomers?
Also, I would like to harvest the seeds to try to grow new shrubs. Is there any particular things I should look for on the seed pods to know whether the seeds are mature enough to harvest? Or would letting the seeds mature take too much energy from the parent shrub?
Thanks for your help,
Julia
Hi Julia, Harvesting the flower heads helps the plant to focus on producing flower buds for next year rather than seeds.
Hi, I pruned down my dwarf lilac bush, it bloomed repeatedly all summer! Was not sure when exactly to prune so did it yesterday. Will it survive the winter ok?
Hi Nancy, I’m not sure where you live, but it should be okay.
Hi. I have two lilac plants, both are lovely, but, the bottom half is just dark and woody, would it benefit from trimming right down?
I would prune out old wood, but if the wood has new growth on top, be careful how far down you prune. Leave some of that new growth.
I planted a lilacs bush 9 years ago !
No flowers I prune it every year
Hi Deanna, at what time of year do you usually prune? It’s possible that you are inadvertently pruning off next year’s blooms.
Hi
I have a lilac bush that appeared of its own accord a few years ago, its not really in the best place. It seems to be mostly suckers with no main stem and blooms right at the top of the stems. I wonder if its best to try and dig the whole thing up? Not sure what’s best to do.
Many thanks
Hi Jackie, Since it appeared out of nowhere, I would try to dig up a stem and see if it does well in another spot in the garden.
My husband in late March pruned back his grandma’s very old lilac tree to about foot from the ground. It was very large but this past year we noticed shredding and some holes we are assuming borers damage. Grandma did not want to lose tree completely and neither did I. Now that it’s been cut back, what types of care and preventive maintenance should I help her with this. We reside in West Virginia and weather is still unpredictable this time of year. And I do not know for certain what needs to be done now it’s been cut and how to keep borers away and to make sure it starts back over healthy..
Hi Cherie, I’m not familiar with this pest, but this article may be useful. https://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/insects/caterpillars/lilac-borer-and-ash-borer.aspx
I have several lilacs in the yard; two bloomed already this year and have lost all of their flowers, but three of my (very tall) lilacs have feathery – blossom/conical shaped growth, but no flowers. I can’t tell if they are going to bloom or not. It’s been a week and no change. Have you seen this before? Writing this in mid-June from the Catskills, NY. Thank you!
Hi Renee, Is it possible the lilac was trimmed later in the season last year, which might have inadvertently removed spring blooms? Or, if it’s a bit older, perhaps a good pruning this year will rejuvenate the plant and help new growth for next year.
Hi! I have a lilac bush that is much too tall to reach for cutting off the wilted blossoms. The ones I can reach, I have snipped off as directed. The bush is growing by leaps and bounds each year. Apparently, my inability to reach has not stopped it from doing well.
Hi!
We purchased some lilac plants this year, from a lilac gardens in Southern Washington. They are all growing, 2 have bloomed.
One plant is growing slowly, straight up, with only the main stem. I’m not sure which kind it is, but it has large leaves. Will it eventually branch, or do I need to do something to it?
Thanks for your advice!
Hi Margaret, You can try cutting it back a bit and see if it forms more shoots next year. Know that if you do this in the fall, it likely won’t flower for you next year.
We recently got a house with 2 lilac bushes in the front yard. They didn’t bloom this year. A neighbor mentioned that they haven’t seen them bloom in years. They seem very spindly. There’s only leaves at the very ends which makes it look very sickly. Can they be cut back? Is there a chance they might bloom again?
Hi Jennifer,
I feel as though you have nothing to lose if you cut them back. However, keep in mind that if they did somehow form flower buds for next year, you could be removing them if you prune in the fall. You may want to wait until spring, see what the plant does and then decide accordingly.
Hello. I live in Michigan and just bought a Boomerang Lilac in a pot that looked dead, but the gardening center assured me it’s just dormant. The ground is now frozen. Do I put the pit outside or keep it in my garage? Do I need to water it? Thanks for your help!
Hi Katie, I would probably place it in a sheltered spot in the garden and surround it in mulch. If you get rain and snow throughout the winter, I probably wouldn’t worry about watering – unless you haven’t had any precipitation recently.
Hi there,
I have a huge overgrown lilac tree. The main stem is at least 3” across. I live in Vancouver BC and it is now mid-April. Is it ok to trim out this huge stem and maybe one other now? Lots of suckers coming up too.
Thank you!
Hi Fran, I would wait until after your lilac has bloomed.
Hello Tara, I have an old lilac that is just not the greatest.
I prune in the spring after they bloom, but I never get many flowers. It’s gotten quite tall, and the top is where the most flowers are!
They don’t even start until where my 5’4 shoulders are!
Now there ARE a lot of shoots underneath. Do I just lop of the top and hope the suckers turn into a bush or just go buy some new bushes? Signed Sad in Ohio:(
Hi Lee,
It’s possible you may need a bigger, more long-term lilac reno. I’ve found some helpful tips in this extension article. https://hortnews.extension.iastate.edu/1993/2-10-1993/lilac.html
Do lilac Bushes benefit from being fertilized? Is so, what kind a should I buy?My large bush is three old and had 7 lilacs this year…the most so far, but makes me jealous when I see others like mine that are chock full of blooms.
I don’t generally fertilize my lilacs, but you can add some in the spring when they first start to produce leaves. Also be sure to prune right after blooming so that you don’t inadvertently remove next year’s flowers.
Hi I’ve got a fairly old lilac tree that blooms every year. I’ve started cutting off the dead flower heads, but I’ve noticed some of the branches are almost bare with a few leaves at the end. Should I cut off these branches completely? Please help 🥺
After your lilac has bloomed in the spring, you can take out the older canes or stems that are 2 inches in diameter or bigger. Only prune one third at a time.
Hello! I have a lilac tree that has been inundated with web worms! The tree now looks dead, although I’m not sure if it is. I was able to remove the webworms from an adjacent lilac tree (it only had a couple and the worms were still in the web) but this one had far too many and I noticed the worms have gone. What should I do for this beloved tree now that the web worms have ravaged it?
Hi Christina, The worms don’t typically cause lasting damage to trees and shrubs. Getting rid of the webs was a good idea and is one of the recommend ways to control them. The tree should bounce back in spring.
Hello Tara – I find your posts very educational and informative. I have an enormous purple flowering lilac cultivar that has been growing since the 60’s. Many of the stems are over 1 inch in diameter, and some are nearing 2 inches – the main trunk is much thicker still. I am
Planning on using an electric pruning saw (functions like a miniature chain saw). I trust that this will be okay, as hand held pruners will not tbey able to cut through the old wood. I plan on doing this in late winter. Is this how you would approach this project. The large shrub is not very florific at this point – probably due to excessive woodiness and lack of fertilizer. We just purchased the house last spring…
Hi Ken,
I’m sure the pruning saw should be okay if it makes clean cuts. If you do this in late winter, you may be cutting off the blooms that formed over the summer. I would wait until after the shrub has bloomed, removing old stems that no longer produce leaves as part of the process.
Hello love lilacs but never done anything with them until reading your advice. I have a very tall 8ft lilac thats 4ft wide. I trasplanted it a month ago during non freezing weather to a spot that will give more sunlight as it was next to the house and was only getting 5 hours of sun. Its March 3rd and see little seed shaped growth on the tips of branches, no leaves yet. Is it still early enough to cut back and how exteme can I get or should I waite till after blooming, usually mid to late May? Many thanks ahead of time for your site and very welcomed advice.
Hi Dan, If you prune your lilac now, you risk cutting off any spring blooms that have formed. I would wait until after it has bloomed to do your next trim.
I have a lilac bush that I did not prune last year. So I literally have a couple of new flowers this year. How do I ensure new flowers for the following year?
Hi Jusi, There are a few reasons why a lilac may not flower. There could be too much shade, too much nitrogen in the soil, a sudden freeze in the spring, etc. If it’s an immature bush, it could also take awhile to bloom. I would assess the planting site and soil to see if any of the above issues could be the cause.
Happy summer!
We have a lilac hedge that is about 50 years old. We trimmed it to within 6″-8″ of the ground last week (after blooms dried up). It’s the second time we have taken it to the ground in 30 years because it grows 15′ high! How/when do I fertilise it to encourage healthy growth next year?
Hi Sherry, The best time to apply a fertilizer (10-10-10) would be early spring when there are signs of fresh growth.
Hi Tara, I bought a house last year and there was a massive lilacs. I pruned it (maybe a bit too aggressively) right after it bloomed. There was also a million shoots everywhere. I pulled roots for days, trying to get the root system out as much as possible. Some times I had to cut them as I couldn’t get the roots out. I was then gone for about a month and came back to a million new shoots everywhere. Some of them are starting to get into my raspberries and some even crossed under a garden bed and started to shoot out in my grass. I really don’t wanna have to pull roots for days twice a year… I was thinking to maybe use round up on the shoots but worried it might kill the actual lilac trees. Unsure of the ange of those lilac trees, but they were probably close to 20 feet tall befits I pruned them. It was so high I could barely pick anny of the lilac flowers.
Any suggestions to deal with the shoots?
Would round up kill the trees and perhaps the raspberries too?
Thank you for any advice you may be able to provide
Hi Caroline, I would not recommend using any type of chemical herbicide in general, but also it might affect your raspberries. And if they did grow, you probably wouldn’t want to eat them. I usually cut the shoots at the soil line with pruners. That might be quicker than pulling them all out. Unfortunately lilacs do throw up suckers as they continue to grow.