How to prune lilac into tree

Tips for pruning lilacs to encourage blooms for next year

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.

Be sure to use sharp hand pruners to trim a lilac bouquet.

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!

To deadhead lilacs, simply snip the dead flower, leaving the stem and leaves in place. If you see next year’s growth, leave it be.

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.

My dwarf Bloomerang in bloom! Cut spent flowers after the spring bloom period to encourage a second growth of flowers in the fall.

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?

Suckers that aren’t close to the actual lilac are simply trimmed at the soil line.

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. 

Pin it!







How to Prune Lilac Bushes

The Spruce / Steven Merkel

Regular Maintenance Pruning

How far you can cut back a lilac bush follows the general shrub pruning rule: Cut no more than a third of the stems each year, starting with the oldest. That will help the plant remain constantly vital, with new stems developing as old stems bloom. Your goal for a lilac pruning diagram is to have a bush with somewhere between 10 and 12 stems, all of them between 1 and 2 inches in diameter.

  1. Prune Unsightly Features

    Begin by pruning dead or diseased stems, pencil-thin suckers that are far from the bush, and twiggy growth. Cut these back all the way to ground level. Pruning shears or loppers will generally handle these stems.

    The Spruce / Steven Merkel

  2. Remove Any Stems Thicker Than 2 Inches in Diameter

    This regular removal of entire old stems will prevent your lilac from becoming too tall. Avoid cutting off just the tops of long stems because this can leave the plant with an odd, unnatural shape. With very large stems, a pruning saw might be necessary. Thick lilac stems can be very tough.

    The Spruce / Steven Merkel

  3. Trim Remaining New Stems

    If you want your lilac to fill in more and become shrubbier, trim the remaining new stems to an outward-facing bud. This means pruning just beyond buds that face away from the center of the plant. This technique will cause more branching and create a denser shrub.

    The Spruce / Steven Merkel

Rejuvenation Pruning

Older lilacs can have stems as thick as small trees and will flower only on the topmost branches. Fortunately, rejuvenation pruning can revive an old lilac in about three years' time. There are two approaches you can take.

The less drastic approach to getting an overgrown lilac back into shape is to use the "third" rule. Prune a third of the oldest branches all the way to the ground each year for three consecutive years. Start by taking out the thickest stems first. Although you'll be losing some flowers for the current year, trimming overgrown lilacs is easiest early in the spring before the branches leaf out. After three consecutive years of pruning your overgrown lilac in this way, new shoots should comprise the bulk of the plant. The plant will begin to bloom all over, and you can do regular maintenance trimming from that point on.

If you can't stand the look of your old lilac or you just want a quicker approach, you can take the drastic measure of cutting back the entire plant to about 6 to 8 inches above the ground in the early spring. Fertilize the plant with compost or a balanced fertilizer to prompt new growth. New shoots will develop throughout the growing season; let them grow through the summer. The following spring, begin pruning out the spindly growth, and maintain the healthiest shoots while considering the shape of the plant. Encourage branching by cutting back the remaining shoots to just above a bud. Carry on with regular maintenance pruning after this.

Working With Japanese Lilac Trees

The Japanese lilac tree (Syringa reticulata) is a plant that can grow as high as 30 feet and has become increasingly popular in urban environments. It has a vase-shaped crown with spreading branches, and it produces showy white flowers in June.

Consistent with their tree-like shape, these plants should be pruned in the same manner that most small trees are handled. Prune to maintain an open interior and several main branches that form a vase shape. Lilac trees generally require little, if any, pruning until they are a few years old.

After this, any necessary pruning should be done immediately after the flowering period is over. Remove dead or diseased branches, as well as any branches that interfere with the overall vase shape or clutter the interior of the tree. If the lilac tree grows too tall, you can cut back individual branches to around 1 foot below the desired height to prompt dense growth at the top.

Tips for Pruning Lilacs

Dwarf lilacs, such as ‘Palibin’ Meyer lilac (Syringa meyeri ‘Palibin’) and ‘Miss Kim’ Manchurian lilac (Syringa pubescens ssp. patula ‘Miss Kim’), look similar to the common lilac. However, how to prune these lilac bushes differs. They rarely require maintenance pruning, though you can trim when necessary for shape.

Like other lilac varieties, they also can benefit from deadheading. Deadheading is the practice of removing dead blooms from a plant by hand. With some plants, this helps to stimulate continuing blooms.

New lilac plants should begin blooming within two to five years. Deadheading the spent flowers will encourage new bud development for the next spring. However, once the plant has matured, it won't need this encouragement, and you'll likely have so many flowers that the task would be too time-consuming.

As with any plant, some years your lilac will bloom magnificently and some years not so much. Blooms are often dependent on the weather. A pleasant summer during which healthy new growth develops will reward you with abundant blooms the following year. A summer with extreme weather will yield fewer flowers. So don't panic if your lilac isn't as vibrant from one year to the next. As long as the plant is healthy and you keep up with maintenance pruning, the flowers will follow.

How to Grow and Care for Lilac Bushes

How to cut lilacs. Lilac pruning correctly. In the spring?

By Oksana Jeter 05/12/2017 Garden-decorative, In the garden, Spring in the garden, Summer in the garden, My garden in the south of England, Gardening technology 10 comments

Lilac pruning in spring? How to prune lilacs correctly

How to prune lilacs correctly, whether to prune lilacs in spring and whether lilacs can be prune at all - such questions are often asked by gardeners. Meanwhile, it is necessary to cut the lilac, otherwise the flowering of this beautiful plant will be scarce and mainly at the very top of the bush, and the lower part and middle will consist of bare lignified branches. Read our article on when and how to properly prune lilacs.

The most common type of lilac in our gardens is numerous varieties of shrubs common lilac (Syringa vulgaris) , which this article is about and which we will simply refer to as lilac .

The largest lilac inflorescences appear on branches aged 2 to 5 years. Lilac blooms only on well-ripened wood of the previous year. The older the branches become, the smaller the inflorescences and the higher they are located. At the level of human growth and gaze, the old lilac branches become stiff and bare. From these features of the lilac vegetation, it becomes clear that this plant, like no other, needs proper pruning. Old and neglected lilac bushes require strong rejuvenating pruning.

Pruning lilacs in spring…

…may not be the best idea if you expect to see blooms this year. If you have extra time, in the spring you can cut branches broken during the winter or shorten branches that do not have buds. The main formative pruning of lilac should be done immediately after flowering, approximately once every two years. This rule applies to all flowering trees and shrubs. Formative pruning immediately after flowering (June) will allow the plant to grow new shoots and form new buds by the time of the next flowering.

As for rejuvenating pruning of old lilac , it is done just in the very early spring, as soon as low positive temperatures are established in the garden (in mild climates, such pruning can be done in winter).

How to prune lilacs correctly: shaping pruning

  • shorten long branches by approx. 1/3
  • thin out the branches near the ground, cutting off excess and old branches at the root
  • cut off (or carefully remove with roots) excess basal shoots if the lilac has grown too wide
  • After finishing pruning, the lilac bush will have a compact, rounded appearance.

    How to prune old lilacs: rejuvenating pruning

    Rejuvenating pruning of old lilac bushes should be carried out as early as possible in spring (if you are not interested in flowering) or immediately after flowering (see photo diagram *, enlarged):

    • shorten all branches to about 30-40 cm from the ground
    • thin the branches near the ground by cutting off excess or old branches at the root
    • cut off (or carefully remove with roots) excess basal shoots if the lilac has grown too wide

    After the rejuvenating pruning of the lilac, the bush will look like a lot of stump branches, but very soon new buds and greenery will form on short branches, and in a year the lilac will bloom magnificently (with good care, of course). Fragrant inflorescences are enough for cutting and for a gift to friends. Photo below: lilac in a vase.

    Pruning grafted lilacs

    Peculiarities of pruning grafted lilacs are that pruning should be done ABOVE the grafting site. All side shoots should be removed, because. flowering on it will correspond to the type and variety of the rootstock, and not the highly decorative scion that you are counting on.

    Lilac shaping and rejuvenating pruning system

    In my garden I use this system as the most practical one. In our conditions, the lilac just grows wildly, so I left 2 bushes and strictly maintain them in a compact state, 2-2.5 m, by alternating shaping and rejuvenating pruning. One year, immediately after the end of flowering, I rejuvenate bush 1 to ground level and remove excess basal shoots (preferably with a root). During the season, bush 1 gives a new shoot from the root, which by the next spring reaches 1-1.5 m in height under our conditions. The following year, in early spring, I shorten this shoot on bush 1 by 1/3 of the height. During the season, new side shoots will appear on bush 1, which will grow somewhere else by 1 m. In May next year, bush 1 will bloom gorgeously, and after flowering it will again undergo strong anti-aging pruning. This cycle is repeated for clusters 1 and 2 in turn in different years. Thus, every year I have a lush lilac bloom in my garden, but the bushes do not grow old and do not grow unnecessarily.

    After pruning lilacs

    After pruning, fertilize lilacs with nitrate and phosphorus fertilizers, and then thoroughly mulch. Lilac prefers neutral soil acidity, keep this in mind when mulching (see the link above for the features of different types of mulch).

    See also: Pruning fruit trees in spring, Pruning berry bushes

    In the UK and some other countries, it is not customary to pick a lilac, give it as a gift and put it in a vase at home. Intrigued, I found an interesting explanation for this custom on the Internet. It turns out that before the widespread use of modern embalming agents, lilacs during the flowering period were widely used in houses where the body of the deceased was awaiting burial, to mask the smell of decomposition. So, on the basis of unpleasant associations, a sign arose that the lilac at home brings misfortune and death. If you are visiting someone in a hospital in an unfamiliar country, choosing flowers, it is still best to stay away from lilacs so as not to inadvertently upset the patient or his relatives.

    * Photo schemes adapted from the magazine
    Fine Gardening

    Tags: trees & shrubs, pruning, lilac, flowers in a vase

    About Author

    Lilac pruning. Basic Rules and Tips


    Tips, Care Views: 60 103 0

    Lilac belongs to shrubs for which correct and timely pruning is extremely important. She cannot be neglected.

    This article is a continuation of material "Rules for planting and caring for lilacs" .

    Sanitary and shaping pruning

    Sanitary pruning is best done in early spring (March - early April) and in summer immediately after flowering. However, if it was not possible to hold it in the spring, then one summer one will be enough.

    In the spring, remove all broken, damaged, frost-bitten branches (may form even in winter-hardy varieties if there were strong temperature changes) during the winter. It is also necessary to cut off the shoots that have grown under wet snow in early spring.

    Last year's growth is also removed if it is not necessary for propagation by layering: a large number of growth takes moisture and nutrition from the main plant, and also increases the size of the bush and worsens its appearance.

    In spring we do not recommend trimming lilacs in height and performing formative pruning: there is a risk of removing flower buds that are located on the top of the shoots.

    Formation pruning, as a rule, is combined with summer sanitary and carried out after flowering. The measure includes:

    • removal of branches that thicken the crown too much, weak non-viable shoots and shoots with dried tops and bases;
    • cutting off shoots affected by pests and thinning the crown;
    • removal of old branches, crossing shoots, small branches growing inside the crown;
    • trimming the tops of the branches to form a beautiful and even crown.

    Do not forget about the newly appeared growth, which also needs to be cut out.

    [stextbox id="info" caption="Advice" ccolor="000000" bgcolor="F4B0FF" cbgcolor="F4B0FF" bgcolorto="F4B0FF" cbgcolorto="F4B0FF"]After sawing off large branches, cover the cut with garden pitch. So you prevent the defeat of plants by infectious diseases.[/stextbox]

    Rejuvenating pruning

    This type of pruning is relevant for aging native-rooted lilac bushes, both varietal and specific. If there are already few shoots on the old branch, then cut it down to the ground. Within 2-3 years, replacement shoots will form from the young shoots.

    We do not recommend replacing all the old skeletal branches at once. It is better to do this gradually, 1-2 branches per year. Thanks to this, the plant will rejuvenate without losing its decorative effect.

    On grafted lilacs, rejuvenating pruning is carried out up to the trunk above the grafting site. An insulating material, such as garden pitch, is applied to the cut site.

    Pruning to regulate flowering

    Lilacs have a peculiarity - if one year it bloomed too abundantly, then the next year the flowering will be very weak.

    For this reason, regular pruning is necessary to ensure that the shrub blooms evenly throughout the year. It is carried out in early spring, before the start of the growing season. At the same time, part of the shoots with an excess number of flower buds is removed.

    Common lilac ‘Beauty of Moscow’

    Pruning of faded inflorescences

    This type of pruning is needed for laying next year’s flower buds on lilacs.

    If faded panicles are not removed in a timely manner, then the nutrients of the plant will be used for fruit ripening, and the number of new flower buds will decrease significantly.

    Never break or pluck out faded panicles. They only need to be trimmed, leaving small stumps.

    Cutting for bouquets

    Cutting flowering branches also activates the emergence of new flower buds. However, they should not be abused - we advise you to leave about half of the inflorescences on the bush.

    By cutting everything, you give the plant a signal to form a large number of new shoots, which will begin to grow everywhere, break the shape of the crown, and also deplete the plant.

    Do not break flowering branches: lacerations can lead to plant disease.

    Use a sharp garden tool to cut into bouquets. Pruning should be sufficiently long shoots up to two-year-old wood, while leaving no stumps.

    It must be understood that when pruning lilacs, we are primarily pursuing the goal of obtaining abundant and strong flowering. Getting enough light, moisture and air, in the crown of a properly formed lilac, each skeletal branch has its own segment for development. Ultimately, pruning forms such a crown through which, as gardeners say, in winter a sparrow can fly without hitting branches with its wings.

    Learn more