All lilacs should generally be clipped right away in the spring after they have finished blooming. Lilacs set their flower buds for the following year immediately after the current year’s flowers have faded, therefore trimming later in the summer or fall will result in the removal of most or all of the blossoms for the following year. The larger common lilacs as well as the shorter or more “shrub like” cultivars are all subject to this timing guideline. While the “when” of lilac trimming is rather simple, the “how” is a little more difficult. For the time being, we’ll refer to lilac pruning as either maintenance pruning or rejuvenation pruning to keep things simple.
When should you prune a lilac bush?
A lilac shrub needs to be pruned every year once it has reached the age of two. Early summer is ideal for cutting grass because the flowers have already flowered and withered. Here are some tips for taking care of lilac shrubs and trees.
Lilacs produce the flower buds for the following season in the early summer, right after their blooms have faded. You run the danger of removing the budding buds if you delay trimming until later in the growing season.
This also holds true for lilacs that bloom twice a year, like Bloomerang Purple. After the bush’s initial bloom, you can prune it to promote new growth and more flowers in the second bloom, which occurs in early fall.
Lilacs eventually only bloom at the tips of their highest branches if allowed to develop naturally. Lilac bushes can be revitalized and made more visually appealing by pruning to maintain a balance between older stems and young blossoming branches.
Pruning a lilac shrub involves a number of techniques:
- First, remove any weaker branches and any dead, broken, or diseased stems. Branches should also be trimmed to avoid rubbing or crossing.
- Old stems that are thicker than two inches should be cut off. This controls the height of your lilac plant and promotes the development of new shoots. It is best to thoroughly remove the stems.
- Control sucker emergence. Suckers are fresh branches that sprout from the plant’s base. The main branches can be replaced by a few robust suckers, but any lesser suckers should be removed at the soil line to prevent them from robbing the plant of nutrients.
Last but not least, here are some general guidelines for pruning lilacs:
- Lilac bushes that are mature should only be pruned to a height of 6 to 8 feet.
- Aim for 10 to 12 primary stems, each of which should be between 1 and 2 inches thick.
- Never remove more than one-third of the bush with pruning.
- Older stems and fresh blossoming shoots should be balanced.
How should a lilac bush be trimmed?
Lilacs are a nostalgic flower for many individuals. On our property in Kansas, my mother planted a lot of lilac bushes. As I played, the aroma spread across the yard. In order for our children to share the same exquisite recollection of the aroma and flower, my husband and I made it a priority to plant a lilac in our garden when we first started our family.
I’ve tried, and have failed, through the years to bring this flower’s bounty into my house. Even though I had the flowers in a spotless vase filled with new water, they would begin to wilt an hour after I brought them inside. I have figured out how to make the blooms last as long as possible by trial and error:
As you trim blooms, have a pail half-full of fresh, chilled water nearby. Choose a chilly morning or evening to pick flowers. Lilacs bloom very sporadically after being harvested, so look for stems with at least 75 percent of their flowers open. Next, remove all of the leaves to prevent the plant from exerting extra energy to keep them moist. Put stems in the liquid. Allow the flowers to absorb water in the bucket for at least an hour by placing it in a cool, dark location.
Recut the stem ends next with powerful clippers, then make 1-2 inch vertical slices up the stem. Take hold of the sliced stem’s one side and twist it backward. Reintroduce the chopped stems to the water in the bucket right away. For an additional hour or two, let the stems soak up extra water in a cool, dark location. After that, the lilacs will survive three to four days and be ready for arranging.
How much can lilacs be pruned back?
Cutting no more than a third of the stems from a shrub should be the general guideline when pruning it. While a result, the plant will continue to thrive and grow new stems as the old ones bloom. Your aim is to grow a lilac bush with between eight and twelve stems, all between one and two inches in diameter, and of varying ages.
Prune Unsightly Features
Pruning should start with the removal of diseased, dead, and pencil-thin suckers and twiggy growth. Trim these all the way to the ground. These stems are typically handled by pruning shears or loppers.
Remove Any Stems Thicker Than 2 Inches in Diameter
By routinely removing entire old stems, you can keep your lilac from growing too tall. Removing only the tops of lengthy stems might cause the plant to take on an unusual, unnatural shape. A pruning saw could be essential for stems that are quite large. It can be difficult to handle thick lilac stalks.
Prune Remaining New Stems
Pruning the remaining new stems to an outward-facing bud will encourage your lilac to fill out more and develop a shrubby appearance. This entails trimming just past buds that point away from the plant’s core. A denser shrub will result from this technique’s increased branching.
How can lilacs be pruned to produce more blooms?
Cutting off the tops of stems that have grown out of control is frequently insufficient when pruning lilacs. It is typically preferable to remove the entire stem. The best way to trim lilacs is with clippers. To avoid spreading and promote later blooms, remove spent blossoms right down to the stems. Three-quarters of the branches should be pruned. Remove any shoots that are emerging from the main trunk and are growing close to the ground. Lilacs within the inner branches may need to be trimmed in order to increase air flow or let more light through.
However, it may be essential to prune the entire bush or tree to approximately 6 or 8 inches (15-20 cm) above the ground if lilac shrubs are already too big or starting to look unpleasant. Remember that it takes around three years for flowers to grow after the entire bush has been removed, so you might have to wait.
Can I remove the entire lilac bush?
The lilac tree will resemble nothing more than a twig in the garden by the end of September. It shouldn’t be reduced to the ground, though. Despite the fact that lilac trees are known for their resilience, it will likely take several years before you see blossoms again because you cut off all the blossoming growth.
If your lilac tree is more mature and unruly, it may require more aggressive pruning and some chopping back; just make sure that it doesn’t take up more than a third of the tree.
How are lilacs prepared for the winter?
When choosing a location for your lilac shrub, consider the winter climate. For this plant to thrive, it requires alkaline to neutral soil and at least 8 hours of direct sunlight per day. Do not place them up against a wall or structure with light colors. Winter burn may be caused by the reflection. Cover the plant’s base with 3 to 4 inches of mulch to help minimize winter heave (the exposing of roots caused by the freezing and thawing of the earth). If a severe freeze occurs in the late winter or early spring, you might need to cover your shrub to keep the new buds safe. You can use burlap, a blanket, or a plastic tent.
What distinguishes a lilac bush from a lilac tree?
Lilac bushes (also known as shrubs) are characterized by their numerous woody stems that emerge from the plant’s base. In contrast, the trunk of the majority of lilac trees is the only woody stem. However, your neighborhood garden center might also sell shrub lilacs that have been grafted onto a single stem to give them the appearance of miniature trees.
The choice between a lilac tree and a lilac bush is typically determined by the amount of space available. Lilac bushes come in a range of sizes and can be placed in more compact areas of a garden. A lilac tree requires space to reach heights of 20 feet and widths of 15 feet. Both need sunlight to flower successfully.
Does pruning lilac bushes harm the flowers?
Your lilac bush will produce more blossoms the following year if you remove the dead flowers. When cutting off your flowers, it’s crucial to only remove the wasted blooms—don’t worry about any nearby stalks. Simply concentrate on the spent bloom’s stem if you can see the two fresh shoots that will grow into blooms the following year. Avoid cutting off the blossoms for the following year!
I now wish to stimulate a second flowering on my dwarf Bloomerang, which ought to happen in late summer or early fall. In order to produce more new growth and blooms during the second bloom season, the spent spring blossoms should be pruned off. A small amount of fertilizer made specifically for woody plants, which I could also use, will help encourage the shrub to bloom once more.
When lilacs are cut, do they blossom again?
The scent of lilacs drifting on the breeze is a sure sign that summer is approaching in Upstate New York. This weekend in Rochester’s Highland Park is the lilac festival! It is practically impossible for us to slip off the farm during this extremely busy time of the year, when field crops are being planted and calves are being born. Although there are over 500 different species of lilacs in Highland Park, I won’t be able to go this year.
Fortunately, we have three lilac plants in our yard, so I get to enjoy the lilacs for the incredibly short period of time they are in bloom. I often arrange a couple containers of cut lilacs for about the house. However, the average lilac bush only blooms for a few weeks each year, so these charmingly fragrant flowers don’t endure very long. The normal blooms barely last five days on average after being cut.
Does new or old wood produce lilac blooms?
What specifically prevents these traditional plants from blooming? Instead of focusing on just one theory, consider a number of potential causes for this issue, including (in addition to illnesses and pests):
- Pruning when it’s not necessary
- The flower buds die in the cold
- placing your lilacs in the incorrect location
- The shrub in question either isn’t old enough to generate flower buds or is too old to do so.
You’ll see that while reasons one and three point to the gardener having done something incorrect, arguments two and four point to no one having done anything incorrect.
Why does it matter what time of day you prune? Shrubs called lilacs produce flowers on rotting wood. This indicates that the flower buds for the upcoming spring’s blooming season have already been formed on the growth from the previous year. When this growth is pruned, the flower buds and, consequently, the blooms they would have produced, are lost. Because of this, it is recommended that you clip lilac bushes as soon as they finish flowering (before they have set bud for next year).
Click Play to Learn How to Prune Lilacs
Despite being a relatively cold-hardy plant, the common lilac (Syringa vulgaris) can suffer harm if a hard frost or freeze occurs just as the flower buds are about to open. As a result, that year’s flowers are lost. You can’t really stop it, so simply accept the loss and look forward to the blossoming twice as much the next year.
Where you put your lilac shrub matters a lot, just like it does with most other plants. Lilacs require full sunlight and prefer well-drained soil. If you made a mistake when you first put your plants on either of these fronts, you can be paying for it today by your lilac not blooming. However, there is a simple solution to the issue: move your shrub to a more favorable location.
Regarding the fourth reason, be aware that although though these bushes have a long lifespan, they do tend to produce fewer flowers as time passes. Implementing a rejuvenation pruning on your lilacs will solve this issue (do not expect immediate results, though). Sometimes, though, the converse is true: your plant may be too young to bloom. Allow some time.
Can lilacs be pruned to preserve a small size?
One of the joys of spring is the luscious aroma of lilacs. The lilac bush, which blooms in late April or early May with clusters of tiny purple flowers resembling bunches of grapes, is a common sight in most communities.
These are primarily common lilac shrubs (Syringa vulgaris). Kris Bachtell, vice president of collections at the Morton Arboretum in Lisle, described it as “grandma’s lilac.” It is widely known.
He said that there are hundreds of cultivated types. Although there are cultivars with magenta, pink, and white blooms as well, the majority bloom in hues of purple. They are all resilient and enduring.
Despite being widely cultivated, common lilac is difficult for some gardeners to grow. Even if some newer types are more resistant to powdery mildew, older ones are frequently deformed by it in the late summer.
The plants, which are native to rocky Balkan hillside soil, require full light and well-drained soil. An older lilac’s blooming cycle may end if nearby trees have grown to shade it.
Lilacs require frequent renewal trimming to reduce their size and thin them out. According to Bachtell, this necessitates the yearly removal of certain elder stems as well as dead wood. Lilacs also frequently sprout suckers from their root systems, which may need to be cut back.
The common lilac can simply be too much of a shrub for smaller yards because it is a large shrub or small tree that grows 8 to 20 feet tall and almost as wide.
Fortunately, Bachtell says, there are alternatives. “He said that several other lilac species are somewhat smaller. “They might be more disease- and shade-tolerant than grandma’s.
Meyer lilacs (Syringa meyeri) can reach heights and widths of 6 to 8 feet. Even though it thrives in direct sunlight, it can tolerate some shade. The flower clusters are smaller but very fragrant, and they emerge a little later than those of the common lilac. Autumn causes the leaves to become yellow. Although there are various cultivars, Palibin is the most popular.
One cultivar, Miss Kim, of the Manchurian lilac (Syringa patula), is primarily recognized. On a plant that is 5 to 8 feet tall, it bears delightfully scented light purple blossoms that turn light pink as they age. In the fall, the ruffled leaves become purple-red. Compared to other garden lilacs, the plant is a little more resistant to powdery mildew.
Hybrid lilacs that rebloom in the late summer or early fall do so less profusely than they do in the spring. Bloomerang Purple (Syringa ‘Penda’), Bloomerang Dark Purple (Syringa x ‘SMSJBP7’), and Bloomerang Dwarf Pink (Syringa x ‘SMNJRPI’) are just a few cultivars in the Bloomerang line. They are all smaller than typical lilacs, although cultivar differences in size should be noted on the label.
According to Bachtell, pruning should be done in the first week or two after the spring shrub has stopped flowering if it’s necessary to keep a lilac untangled and at the right size. Pruning in the winter will destroy buds that might otherwise develop fragrant blooms since lilacs bloom from buds that were formed the previous year.