Pruning lilac bush in fall
Russell Tree Experts — When and How to Prune Lilacs
Please note: This article was originally published on 4/6/2020 and was republished on 6/9/2021.
Common lilacs (Syringa vulgaris) are a favorite landscape shrub here in Ohio and beyond, with flowers that provide beauty and an unmistakable fragrance every spring. Other cultivars of lilacs offer different habits and uses in the landscape, but provide the same display of flowers that we all love. In order to ensure you get the most flowers on your lilac year after year, it’s important to know when and how to prune them.
When To Prune
As a general rule for all lilacs, they should be pruned immediately after they’re done flowering in the spring. Since lilacs set next year’s flower buds right after the current year’s flowers have faded, pruning later in the summer or fall will result in cutting off many or all of next year’s flowers. This rule of timing applies to the larger common lilacs as well as the cultivars that are shorter or more “shrub” like. While the “when” of pruning lilacs is fairly straightforward, the “how” gets a little trickier. To keep things simple for now, we’ll think of lilac pruning as either maintenance pruning or rejuvenation pruning.
How To: Maintenance Pruning
For any lilac shrubs that have not outgrown their space or are still producing vibrant flowers each year, regular pruning can simply consist of any shaping that you choose to do along with removal of dead, diseased, or broken stems. You can also remove spent flowers from your lilacs to help encourage a cleaner growth habit and appearance. It’s always better to do this type of pruning by hand, rather than shearing. When making cuts, try to cut back to an outward facing bud. A good pair of hand pruners is the perfect tool for this and makes for much better pruning cuts than hedge shears.
How To: Rejuvenation Pruning
If you’ve ever had an older common lilac in your landscape that went unpruned for many years, you’re probably familiar with their overgrown, unruly habit when left alone.
Many people mistakenly believe that these shrubs have stopped flowering at this point. Oftentimes what’s actually happening is the flowers are being produced on just the upper portions of the shrub where the plant has reached a taller height and is exposed to sunlight. Once they’ve reached this stage, we’re often left to stare at bare, woody branches at eye level and below. For these overgrown shrubs, we can remove entire older canes or stems that are 2” in diameter or larger to encourage a rejuvenation of the shrub. We want to apply the rule of thirds when doing this type of pruning - Remove approximately one third of the older canes or stems each year for 3 years. This gives the shrub a chance to slowly transition back to a fuller, shorter shrub with more new growth filling in from the bottom. If you decide to drastically prune the entire shrub this way all at once rather than just a third of it, a little extra care like fertilization and watering will be important to encourage new growth.
Note that this “all at once” approach is generally not recommended for the health of the shrub.
Your lilac flowers can be influenced by many things, including the temperature, soil conditions, even disease and insect problems, but proper pruning goes a long way to ensuring they put on a great show every spring. And remember, if you have specific questions about pruning or anything tree and shrub related, your dedicated Russell Tree Experts arborist is only an email or phone call away.
*New* Video!
To accompany the above article, Walter Reins demos how to prune lilac trees in this new video! Click below!
How to Prune Lilacs Like a Master Gardener
Photo: istockphoto.com
When considering how to prune lilacs, keep in mind that those shrubs reportedly flower better on newer wood, so you can do them a favor by removing some of the oldest canes. But “newer” is a relative term. Blooms usually don’t appear on wood younger than 3 years old, while 5- to 8-year-old canes generally produce the most flowers.
Therefore, your lilac bush care routine needn’t include pruning for a young shrub, except the deadheading of faded flowers and removal of dead or broken branches. However, once the lilac reaches 6 feet or so in height, it might appreciate rejuvenation pruning.
RELATED: How To: Plant a Bush or Shrub
When to Prune Lilac Bushes for Regular MaintenanceIf you are debating on when to prune lilacs, the simple answer is that they should be pruned within 2 weeks after they finish blooming in spring. Cutting at any other time of year would be a mistake, since it’s during summer that lilac bushes begin making buds, which persist over winter for the next spring’s bloom.
However, should you prefer to prune when the plant is free of foliage, you can do so in late winter, even though you’ll be removing potential flowers that way. No matter which trimming option you choose, follow the steps below to learn how to prune a lilac bush.
- Disinfectant
- Bypass pruning shears
- Bypass loppers
- Pruning saw
Photo: istockphoto.com
It helps to know that these steps include routine maintenance pruning (which is minimal for lilacs) and rejuvenation pruning. When applied to pruning lilac bushes, rejuvenation pruning can suggest a drastic cutting back of those shrubs in late winter—to within about 6 inches from the ground—to promote all new growth. However, such extreme measures will eliminate all blooms for at least 1 or 2 years, since lilac buds begin forming soon after they completed their last spring’s bloom.
When trimming lilac bushes for rejuvenation, therefore, most gardeners prefer to remove a third of the oldest canes annually for 3 years. That way, youthful vigor can be restored gradually without eliminating blooms.
Before pruning lilacs, soak the blades of your tools in a sterilizing solution—such as 70 percent rubbing alcohol or Lysol disinfectant—for 5 minutes to prevent the spread of disease.
Then, rinse the blades in water and allow them to dry before use.
Photo: istockphoto.com
Begin pruning lilac bushes by removing all of the shriveled blooms as they fade. To do so, find the first pair of leaves beneath a faded flower cluster and snip just above those leaves. You should be able to use bypass pruning shears for this, unless the stems are larger than ¼ inch in diameter. In that case, try bypass loppers instead.
STEP 2: Remove dead, broken, larvae-infested, or rubbing canes at the base.For the next phase of your lilac care routine, remove any canes that appear damaged or infested with pests such as the lilac borer. (Small holes at the bases of shoots, accompanied by sawdust, often indicate borers.) Where two canes are rubbing together, remove the weakest one to prevent it from damaging the stronger one.
STEP 3: To rejuvenate the bush, prune 1/3 of its old canes.
Photo: istockphoto.com
If your bush has aged enough to require rejuvenation pruning, cut out a third of the oldest (largest in diameter) canes, snipping them off at the base. You probably will need bypass loppers instead of bypass pruning shears for this. For canes larger than an inch in diameter, use a pruning saw instead.
STEP 4: Remove all suckers on grafted bushes and most suckers on others.If your lilac is a grafted shrub, your lilac bush trimming procedure should include removing all of the suckers (new shoots that spring up at the base of the plant). Unless you’re growing a living fence, remove most of the suckers for a bush growing on its own roots, leaving only enough suckers to replace the older canes that you pruned.
RELATED: 12 Fall Landscaping Mistakes to Know and Avoid
STEP 5: Remove another 1/3 of the oldest canes annually for 3 years.Photo: istockphoto.com
After your lilac is a few years old or about 6 feet tall, remove another third of the old canes during the next spring, and repeat the process once more the following spring.
Once all of the oldest growth has been cut out, you can allow the shrub to grow unchecked for about 3 years, after which point you should repeat the rejuvenation process.
If you are looking for information on how to propagate lilacs, keep in mind that the cuttings should be at just the right stage to root properly. Those that snap promptly when you bend them are the best fit for propagation. If the cuttings are too young and tender or too old and tough to snap, they probably won’t work. Snip 3- to 5-inch cuttings with at least two leaf nodes each and follow these directions for rooting softwood cuttings.
Pruning lilacs in autumn: how to prune?
Abundant flowering of lilacs in spring largely depends on how correctly and timely the autumn pruning of shrubs is carried out. It is useful for beginner gardeners to learn how to rejuvenate and form a lilac bush in the autumn, so that the next year it will be strewn with many elegant inflorescences.
Dmitry Mayorov
Pixabay
How to rejuvenate a bush and make a lilac bloom: simple pruning rules.
Contents of the article
To preserve the decorative effect of lilac, which consists primarily in lush flowering, it is necessary to regularly trim the shrub. If this is not done, then much fewer flower brushes are formed, since the root system cannot cope with the excess number of branches and the plant simply does not have the strength to form flowers.
The need for autumn pruning of lilac bushes
Lilac bushes need to be pruned regularly for proper development. This is due to the fact that excess branches take food from the root system, and therefore the number of beautiful lilac inflorescences decreases.
Autumn pruning is considered more beneficial for the plant, because at this time it prepares for winter and is at rest.
Pruning lilacs in autumn is required for the following tasks:
- laying more flower buds on the remaining branches;
- forming the crown of the desired shape;
- prevention of insect pests and various diseases to which neglected bushes are more susceptible;
- shrub rejuvenation.
The disadvantages of pruning lilacs in autumn include the fact that beginners in this business need to be very careful in this procedure so as not to accidentally remove the emerging buds. This can prevent the lilac from blooming abundantly in the spring.
Technology of autumn pruning of lilac bushes
In autumn, lilac pruning is recommended to be carried out at least 3-4 weeks before the onset of stable frosts. You can cut a shrub according to several schemes.
Sanitary pruning of lilacs
Every autumn, during the preparation of lilacs for winter, all bushes should be carefully inspected in order to identify and remove:
- dried, broken and crooked branches;
- shoots growing inside the bush, as well as competing and crossing;
- old, cracked and lichen-covered branches;
- superfluous young shoots thickening the crown;
- faded brushes if not trimmed in summer.
If the plant has been grafted, all growth below the grafting point must be cut out.
Formative pruning of lilac
The crown of lilac is formed after the third year of life for several years:
- Choose no more than 4-5 strong strong shoots, well spaced. All the rest are neatly cut down near the ground. The tops of the left skeletal branches are cut at the same height.
- A year later, they work with branches on skeletal branches. They leave the most developed shoots located in the upper tier and directed outward. The branches going inside the bush, intersecting and thickening the crown, must be cut out.
- The following season, a similar operation is carried out, trying to avoid visible voids in the crown or excessive thickening of branches.
In the future, it remains only to maintain the received form.
Rejuvenating pruning of lilac
A neglected and old bush (over 10–12 years old) needs rejuvenation:
- Remove old, diseased, dry, thin, broken and other extra branches.
- A few (4–5) shoots are left, which are cut to 10–15 cm.
Timely and competent autumn pruning helps to preserve the beautiful appearance of lilac bushes, and is also a guarantee of future abundant and luxurious flowering.
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Lilac pruning in autumn: how to do it right
To preserve the decorative effect of lilac, which consists primarily in lush flowering, it is necessary to regularly cut the shrub. If this is not done, then much fewer flower brushes are formed, since the root system cannot cope with the excess number of branches and the plant simply does not have the strength to form flowers.
The need for autumn pruning of lilac bushes
Most gardeners prefer to prune lilac bushes in early spring - before the start of sap flow or immediately after flowering. It is not recommended to do this in the fall, since you can remove the emerging flower buds. But autumn pruning is much easier for plants, as they are already preparing for wintering and are at rest. Therefore, subject to certain rules for lilacs, this procedure will be very useful.
Autumn pruning is more tolerated by shrubs
Autumn pruning is required for the following tasks:
- laying more flower buds on the remaining branches;
- forming the crown of the desired shape;
- prevention of insect pests and various diseases to which neglected bushes are more susceptible;
- shrub rejuvenation.
Autumn pruning of lilacs is carried out for sanitary, shaping and rejuvenating purposes
Technology of autumn pruning of lilac bushes
In autumn, lilac pruning is recommended at least 3-4 weeks before the onset of persistent frosts.
Shrubs can be trimmed in several ways.
Autumn lilac pruning can be carried out according to different schemes
Video: lilac pruning scheme
Sanitary pruning
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- withered, broken and crooked branches;
- shoots growing inside the bush, as well as competing and crossing;
- old, cracked and lichen-covered branches;
- superfluous and thickening young shoots;
- faded brushes if not trimmed in summer.
Sanitary pruning removes all unnecessary, unnecessary, old, broken and diseased branches.
Video: autumn pruning of lilacs
Forming pruning
The crown of lilacs is formed after the third year of life for several years:
- Choose no more than 4-5 strong strong shoots, well spaced.
All the rest are neatly cut down near the ground. The tops of the left skeletal branches are cut at the same height. - A year later, they work with branches on skeletal branches. Leave the most developed shoots located in the upper tier and directed outward. The branches going inside the bush, intersecting and thickening the crown, must be cut out.
- The following season, a similar operation is carried out, trying to avoid visible voids in the crown or excessive thickening of branches.
Formative pruning of lilacs is carried out after three years
In the future, it remains only to maintain the resulting shape.
I like to shape the lilac into a tree shape. To do this, I leave one central branch, which will be the trunk. I remove all the rest. Upon reaching the desired height, I pinch the stem, stopping its growth. Then I choose four strong outward branches and work with them in the future. I constantly get rid of unnecessary growth.
Standard lilac is formed in the form of a tree