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pruning lilacs

lilacsEXCEPT IN THE warmest zones, where they are basically disinclined to bloom, every garden should include some common lilacs (Syringa vulgaris) or their various beautiful cousins, old-fashioned shrubs that couldn’t be easier to grow. Given full sun, good air circulation (to lessen the incidence of powdery mildew) and proper pruning, they produce profuse numbers of fragrant flowers. If lilacs fail to bloom, it usually means they have been deprived of sufficient sunshine—or pruned at the wrong time.

Like other spring-blooming woody plants, the lilac produces its flower buds from late summer through fall for the following year’s display. Prune after, say, July 4th in the north and you risk reducing next year’s bloom. Prune in fall or early spring, and you guarantee that disappointment.

A lilac is happiest if you cut bouquets from it each spring—essentially you are just deadheading it. Though not essential to its health or survival, the lilac isn’t really asking much from you but paying heftily, since the trusses make extravagant indoor arrangements. You work a little, you win. (A tip: before bringing the cuts inside, hammer the bottom few inches of the stem ends on a hard surface like stone to crush them, so they can drink up the water in a vase, or the flowers will wilt almost at once.) Bonus: By harvesting flowers you avoid the unsightly issue of all those large, dried-up flowerheads that hang on tenaciously all year.

Always cut out dead, damaged or diseased wood as it occurs on any shrub or tree, and likewise with suckers that sprout from the base (and may in fact be growing from the rootstock if it’s a grafted plant). Sometimes a lilac needs reshaping. Conventional gardening wisdom says any shrubs can be “rejuvenated” over three years by cutting one-third of its oldest stems to the base each year, but I ask this: Look at your lilac (or any other shrubs) carefully. Sometimes you don’t want to reinvent (a.k.a. “rejuvenate”) the thing but just to tweak it, so look and think, and look some more before the saw comes out. I like the way Jeff Jabco of the Scott Arboretum of Swarthmore College explains the various stages of the pruning process—whether the yearly flower-harvesting kind or the more ambitious undertakings.

If you want to visit my lilac collection, here it is, and to make your cut bouquets last, read on.

Related posts:

  1. lilac pruning (and perfuming)
  2. pruning roundup: what shrubs i prune when
  3. from the forums: pruning viburnums
  4. pondering a bout of mid-winter pruning

Comments

  1. andrewoowoo says:

    Wonderful blog, Margaret! I toured your garden in 2006 and the experience was more than memorable. What a wild and wonderful and vibrant place. Glad I found the blog!

    -Andrew in Ottawa

  2. margaret says:

    Andrew,
    I am so glad you found me so soon! I haven’t even begun reaching out to garden friends–the site’s just 11 days old, and you are among its first visitors. A very good omen indeed.
    M.

  3. andrewoowoo says:

    M,

    I’ve heard from a number of people via my blog – a sort of reader’s appreciation of all things Martha marthamoments.blogspot.com – that they are eager to hear about what you do next. It was one of these visitors who informed me of the site, which I’ll happily promote. I’ve heard rumours from your MSLO peeps that a new book may be in the works, too? I hope so!

    Your guidance of the magazine was truly wondrous, M. dear, but this new chapter seems ultra exciting! Please see my blog for photos of your garden and a rather loving testament to its beauty.

    I’ll be visiting this blog often.

    -Andrew R.

  4. margaret says:

    …and I hope visiting the REAL garden too again someday. Thanks for all the good wishes. We can look forward to spring together.
    M.

  5. mary kate mccarty says:

    Hello Margaret,
    I’m a friend of your sister, who was my (superb) writing instructor.
    After visiting the Cotswolds in May a few years ago, I am a passionate novice. Lilacs, peonies and hydrangeas are my favs, and fortunately they seem to do well here in Troy, NY.
    I’m planning to plant lilac bushes soon and wonder if you have heard of the Miss Kim variety? I planted one at my Cape Cod home, and it hasn’t done very well there.

    Your site is amazing – so thorough and comprehensive. I’ve recommended it to some friends who have not gardens but “parks” akin to the Cotswolds, and I’ll continue to pass it along.
    Best of luck,
    Mary Kate McCarty

  6. margaret says:

    Welcome, Mary Kate. I have indeed heard of ‘Miss Kim,’ which is naturally smaller and slower-growing than many of its cousins. Generally lilacs are pretty tough and adaptable, but seashore conditions (sandy soil, salt air, etc.) can be harsh on any plant. Not sure what’s up with it–growing slow, not flowering, dying off in parts? I assume you have given it a sunny location, which it wants to bloom well.
    Do come back and visit–I will open Q&A forums for formal garden help soon on the blog, and there will be new stories posted every day. Happy spring.
    M.

  7. carl ryan says:

    I have a ? for you, when you pick the lilacs and bring them inside they die so fast, what can we do to slow that dying process down, any suggestions please reply asap, thanks

  8. margaret says:

    Welcome, Carl. The details are in the story on this other page, but basically here’s the trick: hammer the ends of the stems (the woody part) to split it so it can take up moisture. Do this outside on some stones or something.

  9. Bonnie says:

    This is from your article “Prune after, say, July 4th in the north and you risk reducing next year’s bloom. Prune in fall or early spring, and you guarantee that disappointment.”
    Sooooo – when is the best time to guarantee blooms in the next year. (Eastern Ontario, Canada).
    I see wild lilac blooming profusely in ditches but not my pampered ones.
    Thanks Bonnie

  10. margaret says:

    Welcome, Bonnie. Lilacs, like other early blooming/spring-blooming shrubs, should be pruned right after bloom. For me bloom ends around Memorial Day or start of June. You get a little leeway after the blossoms fade, before energy goes into preparing to set next year’s buds, which is why I say July 4 is OK, too, but not after.
    When did yours stop blooming? Figure you have a month after that, but closer to end of bloom is ideal/better.
    Once the buds start forming in high summer and onward, any cutting you do will take off would-be flowers.

  11. a in calgary says:

    Lacking time previously, I’ve just spent a week pruning my lilacs. Some I have taken care of well over the years ..so it was just taking off suckers… But there are some that I left unpruned for several years.. really old lilacs + 50 years old with stems from 3 to 1 inch. These are doing poorly…there was so much deadwood. +60% I had left it there to test a theory that the dead wood would provide support during our very heavy spring snowstorms. But now there was so much that I was alarmed. I know its late in the year to prune but I’m looking ahead a few years… I know its late to be feeding our first frost can come within a month Ha Ha .. but it won’t last.. These lilacs have never been fertilized or even watered much unless there was a severe drought… Is it too late to put a layer of compost down and cover it with mulch?

  12. margaret says:

    Welcome A in Calgary: There is never a bad time to apply compost and mulch, but better not to apply actual commercial fertilizer at this time. Good that you seized the day and got on with your pruning, even now…since you had the time. I know how that goes!

  13. Anita says:

    Looking for extremely fragrant lilacs. My yard is small, so I tried Miss Kim – no fragrance at all!! Recently bought Tinkerbelle so hopefully this spring will have fragrance. Any other suggestions for fragrance?

  14. margaret says:

    Welcome, Anita. Yes, ‘Miss Kim’ is a nice size but not sweet to the nose. Did you see the collection of them I posted about last spring? All of those are fragrant, though some are quite large. If you like pink, ‘Marie Frances’ might fit your space. Have a look, and let me know.

  15. Chris Anne says:

    We have nine Miss Kim lilacs, and they are so sweetly fragrant that they just about knock us over. Maybe we have mutants? I actually came searching for pruning instructions for these at my DH’s request, (from whom I must hide the loppers till late spring, as he gets cabin fever about this time of year and is wont to go out randomly hacking) . The MK’s were planted 4 springs ago, and are looking just a bit ragged. They are not in full sun except in early spring, but this hasn’t seemed to discourage blooming, thank heaven. Was just surprised to read that others haven’t found them fragrant.

  16. Margaret says:

    Welcome, Chris Anne. It is interesting about fragrance and how sometimes it is so heavy and sometimes not. Everything I read in reference materials says it’s meant to be fragrant, and apparently you agree. See you soon again, I hope — and tell the DH to watch out and not turn Miss Kim into a blob over there. :)

Comment:

The Sister Project

The Confessional

Some stuff really gets A Way to Garden-ers going. Weigh in, or just lurk while everyone else shares about these hot buttons:

Compost, Compost, Compost

I am as proud of my compost heap as I am of any part of my garden. It is the archaeological record of my garden past; it is the stuff from which future gardens will arise. I read a lot about, from sources like these: Garden Organic, a 50-year-old British charity; Journey to Forever (don’t worry, not some into-the-bunker survivalist cult); and the vast Cornell Composting archive. Dig in.

Juicy Bits

375 VISITORS, 1 BIG RHODIE: spring garden open day, in a virtual visit. How it looked, and also what they all asked about

keeping deer out DEER FENCE: I tried every potion and anti-deer trick till I finally got real and fenced. Strategies for every garden situation.

secrets to great tomatoes TOMATO TIPS, seed to harvest: Dozens of tricks for a better crop.

yes, even in dry shade MY 4 TOUGHEST GROUNDCOVERS perform even in the worst spots, like dry shade. Maybe these tough perennials will serve you as well?

5 great small trees GARDEN-SIZED TREES can’t just be the right scale; they need to have multi-season interest, too, to earn a spot here. Maybe you have room for one of my 5 favorites?

10 underplanting do’s and don’ts MAKING MOSAICS—that’s what I call good underplanting of trees and shrubs with a tapestry of plants for many months of enjoyment. Here’s how I do it.

a ribbeting bullfrog whodunit LET BULLFROGS BE BYGONES? No way. Where have all my biggest frogboys gone? The latest frog mystery explained.

stars of the spring shrubbery BEYOND LILACS (and forget forsythia!), a slideshow of some of the finest spring shrubs you may not grow (yet).

speeding up the compost DRIVE BY, HIT-AND-RUN composting is my latest craze, and speeds up the decomposition process while making good mulch quickly. Here’s how.

making a 365-day garden THINK FALL (YES, FALL): Don’t get sucked in by spring-bloomers only when nursery shopping. A great garden happens 365 days a year: Shop smart to make it so.

the facts about bulbs SOMETHING UP with a flower bulb? Paltry bloom, or wondering when to feed or cut off the foliage? It’s all here.

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12 steps to sanity? HELP FOR GARDENERS: Hi, my name is Margaret, and yes, we operate a 12-Step program here. Welcome.

orchid rebloom made easy I REBLOOMED MY FIRST ORCHID last year (finally!) and it turns out to be pretty easy going. Here’s how.

my seed-starting 101 WHAT ABOUT SEED-STARTING in general? The A Way to Garden method.

crispy refrigerator pickles WHAT IS IT ABOUT refrigerator pickles that makes everybody so happy? Get those cukes growing now. And then some.

hail the stewartia I LIKE PLANTS THAT EARN THEIR KEEP. By that I mean they do more than a week or two of showing off; they look good in more than a single moment, or season. The small-ish to medium trees in the genus Stewartia are a good bet if that’s the kind of multi-season interest you are looking for. Sound good?

can-do pruning REPEAT AFTER ME: I can prune. I can prune. If you follow this simple method for starters, your woody plants will thank you.

the ‘other’ peonies JUNE IS PEONY TIME, the big raucous kind of peony time, but just before that another kind of peony you might want to consider adopting does its subtler, wonderful thing.

which lilac to plant? SO MANY LILACS, so little space. Browse a glossary of some of my favorites before you shop—maybe you’ll like them, too.