Marj - lilac is a cane grower. You can chainsaw the whole thing down and in three years it'll be several feet tall and blooming again. I have a neighbor who has 20-year-old never-pruned lilacs that get fewer blooms and more powdery mildew every year - they just don't do well when they get that big and old.
Personal experience - we were going to take the one in our yard out so I chopped it down to 6" and tried to dig it up. HA! It's fully re-rooted and 4' tall three years later. They do bloom on old wood so yes, you'll need to wait for the flowers to come back. If you can't selectively prune I'd just lop it all back and be patient. :) Then you can just keep up on it afterward. I have a mock orange (also a cane grower) and after I took the whole thing down I now just prune out the oldest/wonkiest canes every 3-4 years and it looks GREAT.
This article gave me the courage:
http://www.finegardening.com/how-prune-cane-growing-shrubs
Also:
http://www.yourgardensanctuary.com/pruning-cane-type-shrubs/
Be brave!

Yep, you have to hack it back! My old one barely bloomed the last two years. Last fall I cut what I thought was a lot of the larger limbs, (they say to cut 1/3 every year). It bloomed a lot better this spring, but I'm going to hack it again.

Good luck.
~Cat

As others have said, you'll need to whack some, or all of it, back - with these huge bushes, it can be a lot of work, and then there's the issue of getting rid of all that stuff you just whacked off.

I've done pretty well by using an electric reciprocating saw and just getting the biggest 10 or so stems, then repeat that next year. That ways, the bush still looks pretty full. And that, you can chop up and they'll take it away with the trash.

I've also just cut them down entirely about a foot off the ground.

But I have a swamp where I throw all my shrub and tree pruning, I don't have to deal with getting rid of it via a bin by the side of the road.

At the end of the day, we have so many late freezes that we rarely get lilac blooms anyway, and then, 18 years ago I bought 50 lilac plants from the Soil Conservancy, so I'm now looking at 53 huge lilacs, and I just continue to look at 53 huge lilacs and if they get a few blooms, thats fine too. :-)

Thanks for all the info/tips/advice! When is the best time to cut it back - in the fall?

We just had to cut down the top half of a Russian Olive in our yard as that part was dead (still some suckers coming up, so the roots are still good - although I don't know that I really want it growing back. It did act as a bit of a screen from the neighbors, but hate the thorns on this tree!). What a job! DH used the chain saw to cut it down, and all the big branches into more easily handled size. Then DD and I broke down all the thousands of small branches off of the main branches. The plan was to then have these piles ready to load up in our truck at the next limb recycling day. But man - what a huge amount we ended up with from that top half of the tree, and many, many thorns!!! I put a ad on craigslist offering the dry wood for firewood or mulch material, and thankfully, many people have stopped by and have helped slowly dwindle down the piles :) Have one guy that has come by 2-3 times already and taken a med size truck load each time for using in his teepee up around Ft. Collins (interesting!). He emailed me yesterday and hopefully will be coming back this weekend to take the rest. That saves us a lot of work loading it up and making several trips to the recycle place!!

So because of that, not looking forward to another bunch of branches in the yard :( Hopefully cutting it back in Sept. would be a better time for the plant, as that would give us a rest as well as still time to get it to the limb recycle before they close for the season. This wood would be way too green for anyone to use as firewood!

Marj

So I found this site on pruning Lilacs: http://www.wikihow.com/Prune-Lilacs. Looks like I can rest till early next spring!

Um, my lilacs have a stem mass of about, oh, 4 - 6 feet in diameter.

They graft lilacs? Who knew?

Hi Misty,

This probably doesn't make much difference since yours is blooming very little anyway, but if you wait to cut yours down till "early next spring," as in before they bloom (or try to bloom), you'll be cutting off whatever flowers you might have gotten next year. Lilacs form the buds for the following spring shortly after they finish blooming in the current year.

Many years ago when "we" (ex and I!) bought a house in Olde Denver, the backyard was so overgrown we didn't even know what we "were getting!" When we cut down two very old and very overgrown spreading junipers we discovered we had a little pond! But included with the rest of the jungle was an apparently VERY old lilac that appeared to be beyond its useful life! Thinking we were "getting rid of it" we cut it ALL the way down, as Amy described above--less than a foot above the ground. I've always been into perennials as opposed to trees and bushes, so I was very surprised when it "came back with a vengeance!" Like Amy, ours regrew into a wonderful "rejuvenated" bush that you couldn't tell hadn't been recently planted after 2-3 years--except it was so much bigger because of the established root system the new growth came from. This was long ago, and I don't remember how long it took, but I believe by the third year for sure we were starting to get some nice flowers, on a bush that was still compact and pretty and required no additional pruning or care yet at that time. It sounds like David's system of cutting out the biggest, oldest, woodiest stems each year works too, and would continue to give you some flowers rather than having to wait for it to come back "from nothing" in the first couple years, but that would require annual maintenance. When we cut ours down we were just trying to get rid of stuff that appeared to have no value anymore, but in retrospect I'm glad we did it that way because it really did result in a very pretty "new" bush!

Whatever you decide to do, plan to do it NOW or else to wait till after it blooms/tries to bloom next spring. If you're going to cut it down all the way, the sooner you do it the sooner it will be able to "come back," so the sooner it will start blooming "fresh" again. If you wait to do that till next spring, it will be another whole year of "flowers lost" since it's not really blooming anymore anyway.

And I way second Amy's comment about the mildew too! The older, less healthy because of it's age, stems and foliage will be far more prone to developing mildew, and with such a "large thing" I'd be inclined to want to get it out of there sooner rather than later just to keep all that "additional" mildew out of my yard. The house I lived in (a rental) prior to my current house also had a very old, rarely blooming, lilac in the yard. Because I was renting I didn't cut it down to the ground (I did prune some of the big olde wood out of it), so it remained tall and always had quite a bit of old growth--and it was ALWAYS covered with mildew by midsummer! And with the "minimal" cutting back I did, it never did start to bloom nicely again like the one we had cut down all the way.

Whatever you decide to do, take some before and after pics and let us see how it's going,
Skybird

Whooboy - not looking forward to this job!! Here's a few pics so you can see what I'm talking about:

Full "bush" - notice how much taller it is than our 6ft fence. I think my guess of 15 ft or more is pretty accurate:

Here's a closeup shot of the mass of stalks (notice the size of them next to my fingers):

And another of the main canes:

I gotta take some time to figure out my approach - a few canes at a time, or mass attack! I don't plan, though, to take it down to the ground in either case - it's too good of a screen from the neighbors yard! I may try just taking it down to fence level, as well as thin it out, and hope that's enough. If that doesn't help it bloom again, I may settle for that. Last year, I managed to dig up a sucker and get it to root, so hopefully at least I'll someday get blooms on that one :)

I haven't noticed the mildew on it, but maybe it's in the interior and haven't seen it. But I'll look for it now. I may just start whittling away at it slowly - since it only got maybe a handful of blooms this year, it won't make any difference as far as that goes for next year when I cut it back - but I thought that was so strange how it sets buds right after blooming for the next season! Wonder if there are other plants that do that.

Loved your story about your hidden pond, Skybird - that must have been a cool surprise!

I get mildew in September. Pretty much on everything, not just lilacs.

Your lilac is the size of my older ones. At the link is a reciprocating saw. If you don't have one, you might consider one - they're one great toy, and after you've used one, you're hooked. There are all kinds of other things they'll come in handy for -

For what its worth, there's a lilac down the road that is enormous, dwarfs the house its planted by - well over the roof, the crown in larger than the house is wide. And it blooms spectacularly any time we don't get a late freeze.

Here is a link that might be useful: saw

Off topic so I'm sorry...

Marj- Do you have any good thorny limbs from that Russian olive left? I need to build some fencing to keep critters out.....

ZachS - yes, still have some! The guy with the teepee keeps saying he's going to come and get them, but hasn't shown up again. So if you want some, however much you want is yours :) Send me a PM and I'll give you my address. Here's a link to the craigslist ad I've had going for awhile, with some pics of some of the wood: russian olive.

David - I think my husband probably has a reciprocating saw. He also has a chain saw. He is having rotator cup problems, so really shouldn't be trying to do something like this right now. I'm intimidated by the chain saw, but maybe I could handle the reciprocating saw.

Gosh, I sure wish mine would bloom like that neighbors of yours - it sounds like an impressive size!! Would love to see it. I wonder what the difference is between theirs and mine. Last year, I thought the weather was the reason ours didn't bloom. But don't think that was the case this year.

I'll be taking a look at what's behind mine and the neighbors yard. They do have a couple of large trees in that area, so maybe our lilac isn't as much as a screen as I'm thinking. If that's the case, then could take it down further.

Marj

This post was edited by mstywoods on Wed, Jun 4, 14 at 9:41

I sent you an email Marj! Thanks!

YAY! Love it! Good going :)

hello, glad your lilac made a comeback. . . I started reading this thread because I had the same problem last season. Not only was mine not blooming but it wasn't letting go of the previous (several) years spent blossoms. It had a few clusters of flowers last year and I decided then and there I was going to introduce it to my new chainsaw. I took quite a bit off the top but more out of the center and the many suckers growing next to it.

I got lucky. As usual, I didn't get any info on doing this, just started hacking away. When I finished I had a huge pile to deal with too. If I had read this 2 weeks ago I would have been really nervous, I did it in the late summer. Not knowing the blooms/flowers came on older branches.

Now it looks like a tree rather than a bush. It has a nice canopy, a lot fuller this year than in the past. It is covered in thousands of clusters of buds waiting to open any day. I can't wait to have vases full of sweet smelling white lilacs setting around. When its done blooming I am going to get in there and take all the spent blooms out.

I still have new suckers to deal with and it is wanting to get branches where I don' want branches (poke me in the face when I'm mowing) but that's OK they are easier to deal with now.

Thanks to all for the helpful info.

My lilac didn't bloom much last year either and I thought it was because it needed to be hard pruned but I never got around to it. This year, it bloomed quite well. And while I still think it needs a pruning and shaping, I'm sort of glad I didn't touch it last yer. As soon as it is done blooming, I'll try to get it pruned so it will be in bettter shape for next year. I sure do enjoy the smell of my backyard!

here's mine

Glad both of yours rebloomed as well! maidinmontana - you are tempting me to cut mine back this year! Mine also has held on to the old spent flowers, so I should at least get on a ladder and cut those off. Would love to see a pic of how yours looks now with all your brave efforts :) I was thinking maybe I should leave the suckers on mine so they would eventually replace the too old (non-blooming) branches - but maybe that's not the right thing to do?

Popmama - yours looks nice with it's blooms! Nothing like the smell of lilac in the air!!

Marj

Marj, I'll try to get out there when its in bloom ( only a few days at most). It sits at the south end of our covered patio and I noticed today there is a lot more shade now than there was in the past, since it has a fuller canopy. Which is another bonus as a result of the hard pruning, since the flowers only last a little while, I will really enjoy the shade when the temps heat up. Mine looks similar to Popmamma's but the canopy starts further up and the bas is just bare. And yes, I must get on the ladder and cut off the spent blooms from last year. (I hate ladders)

I didn't leave the suckers intact (like I said in previous comment, I didn't know the right way to do it when I did it the wrong way :) but my thinking at the time was to get them out so the energy could go to the bigger bush rather than the sides and base, so I took them all out. Your thinking makes sense, I think.

I can't wait to smell lilacs in the air.

Debi

Yea, I hate ladders too Debi!! But sometimes we have to resort to those unfortunately :(

I got a email from Houzz saying you posted a picture on this thread, but I don't see it here. Strange! Did you post one with a new comment?

Marj

Really. . . I have been trying to post for 2 days and my pix wont upload. . . I want to share a pix pf my lilac bush. . . funny they know but still don't help. . . thanks for the nod Marj. . . I'll keep trying.

~Debi

Still don't see your post with the pic, maidinmontana - yet received another email notification from Houzz for your new post. ??? Are you using either the Photo or Houzz Photo icon at the bottom of the compose area? If you use the Houzz Photo, you have to first upload your pic to the site.

Here's a test:

Inserted directly from my computer using the Photo button:

Inserted from the Houzz Photo button, already uploaded to the site:

Just figured out how to resize the photo in the post - double-click the image after you have it inserted, and you get the little squares around the edges. Then you can drag the size of it smaller or larger!

Marj

Hi Marj, I am trying to upload the photo from my computer. I click on the camera icon that says photo. . . I choose the photo but it never finishes uploading. I have let it go for several minutes but the photo never appears. Then when I try to leave the page I get ameesage asking my if I want to leave the page or stay on it, which tells me the photo is still in progress. In the past (garden web days) I uploaded to Photobucket then copied to here, I may try that and see if it works. Or should I upload it to Houzz then from there to here? What a night mare. . . Thanks for the info Marj.

~Debi

Oh this is better. . . lol. . .

Well, we finally pruned back our lilac!!

DH used a pole chainsaw we got this year - it was really helpful - on the big older branches mostly on the inside of the clump. Then I made a tool (husbands suggestion) by taping a hook onto the end of a piece of bamboo, and used that to hook the top branches and pull them down so I could trim them - this saved me from having to get up on a ladder. Worked well!!

So here are the before and after pics. It's a little hard to tell how much we trimmed because of the trees in our neighbors yard behind it. But a lot did come off! Hoping it likes it next spring and we get some new fresh growth and blooms :)

This was taken 6/1/14:

This was taken 9/10/15

And here is my fancy tool for pulling the top branches down:

I hated having more of the neighbors green shed exposed. I keep trying to get something to grow up along that area so it will hide it (the green plant you see there is some type of weed plant that I find in other places in the yard. I let it go this year, that's why it's so tall), but haven't had any luck. Think I need to amend the soil area (we have sand on top of the old grass there, but I have dug up a couple of spots for plants and added some soil) or maybe I should put planter boxes at the top of the fence instead.

Did you trim yours, popmama and maidinmontana? I love that picture of yours, maidinmontana - very pretty! Yours is really tall as well.

Marj

Yea, my Lilac is blooming! Took this a couple of days ago, before the rain/snow today. The blooms aren't completely opened yet, but I think you can see in the pic that there are many that will open soon :) and there are many more than pics I posted in earlier parts of this thread. Overall, it is looking so much better than it has in years!!

Thanks to this group for all the helpful info - never would have known I needed to cut it back to get it to bloom again if it wasn't for all of you!

Looks great mstywoods! Mine bloomed this year too. Right now, it's sagging in the snow.

Thanks Msty. . . yes I trimmed mine. Not a hard prune but I always cut off the spent blooms soon after they are finished. Yours turned out beautiful . . . enjoy the nice fragrance. . .

Debi