Check the growth circumstances for your lilac as your next action.
Lilacs require full sun, or around six hours of sunshine each day. Make sure that no other trees are blocking your lilac’s sun so that it can thrive even in partial shadow.
Mulching around your lilac plant prevents the roots from drying out and aids with weed control. It’s crucial to routinely water lilacs in dry weather. Lilacs, however, prefer well-draining soil and dislike damp, moist roots.
Stop fertilizing your lilac if it isn’t flowering. Lilacs that have received excessive fertilization will produce an abundance of lush growth but not the desired amount of flowers. Lilacs don’t need a lot of fertilizer, perhaps only a modest feeding in the spring. Your lilac can be receiving more food than it needs if you routinely fertilize adjacent lawns or other plants. Your lilac’s soil will benefit from having phosphorus added, such as by using bone meal.
Scale insects and borers can harm lilacs. Check the leaves and stems of your bush to see if a renewal pruning is necessary. Usually, removing the problematic regions will solve the issue.
Why aren’t my lilac bushes blooming?
A. There are a number of potential causes for your lilac’s failure to blossom. Lack of sufficient sunlight is the main culprit. Lilacs (Syringa) should be planted in an area with at least six hours of direct, bright sunlight per day. They can withstand a wide range of moisture levels as long as they are grown in soil with good drainage.
If your lilac is clipped at the wrong time of year, it might not blossom for another reason. Lilacs bloom in the spring on the growth from the previous year, and soon after, they begin to form the buds for the following year. Within a few weeks of the plant blooming, pruning must be done simultaneously with the removal of the wasted flowers in order to prevent the removal of the buds for the following year. A late freeze can harm flower buds on types that bloom early.
Lilacs have a tendency to mature into overgrown, leggy shrubs with minimal foliage at the bottom. When this occurs, it might be required to prune them to within 12 inches of the ground in order to completely rejuvenate them. When the shrubs are dormant in late winter, this should be done. Lilacs benefit from this repair, although their blooming cycle will be hampered for at least one season. Lilacs can receive a rejuvenation pruning over a two-year period to stop the interruption of bloom cycles. Half of the shrub’s stems should be hard pruned the first year, and the remaining stems the following year.
Lilacs do not consume a lot of food. Excessive fertilization, particularly nitrogen fertilizer, can frequently promote luxuriant vegetative growth at the expense of flower development. A lilac’s failure to bloom could potentially be due to its proximity to turf that receives frequent fertilization.
How can I make my lilac flower?
Lack of sunlight could also be a factor in your lilac plant’s failure to blossom.
You can grow lilacs that don’t have blooms in a location that is either shadowed by other trees or something else. It won’t bloom, but it will live.
For the best blooming, a lilac bush needs at least 6 hours of direct sunlight per day. It can be relocated or the trees that shade it can be cut back.
Be patient because transplanting lilacs may cause a one-year delay in bloom. To ensure that sunlight penetrates the foliage, you may also need to thin the bush.
How can a lilac bush be revitalized to produce more flowers?
An old, overgrown lilac was one of the few plants that endured my garden restoration. The fact that it obscured my neighbor’s garage and, more importantly, sported steel-blue double flowers, led me to rescue it. Although the blossoms on this shrub were both lovely and fragrant, it was difficult to appreciate them because there were so few of them. I decided to go with a rejuvenation pruning because I knew there was no reason to give up on this long-neglected plant because lilacs can handle severe pruning.
On stems that are no older than five or six years, the common French lilacs (Syringa vulgaris cvs.) yield the most and the largest flowers. The flowers get fewer, smaller, and farther away as the stems get older. A lilac, however, may reliably produce blossoms for decades with the right trimming. The method you choose will depend on how old your shrub is. Plants are maintained annually to keep them healthy. A more drastic trimming may be necessary for lilacs like mine that have seen better days.
Lilacs should be clipped annually to encourage healthy stem development and strong growth that improves flowering. Cutting sick, deformed, and unproductive stems to the ground constitutes annual pruning. I thin and cut back some stems as well to promote healthy, evenly spaced growth. To prevent them from growing too far away from the center of the plant, I also pruned a few of the new shoots that emerged from the roots. I left a few inches between each stem to prevent crowding. Since they produce the most, I maintain the pencil-thick shoots that extend all the way to the ends of the branches. Small, twitchy growth is unproductive and won’t blossom. This growth can indicate an excess of aged, unproductive stems or too much shadow. Remove stems as soon as possible after blossoming, or in late winter if you don’t mind losing a few blooms. Cut off stems and shoots at or just below the soil line.
Dwarf lilacs rarely need pruning
Both the “Palibin” Meyer lilac (Syringa meyeri “Palibin”) and the “Miss Kim” Manchurian lilac (Syringa pubescens ssp. patula “Miss Kim”) are twiggy-habiting, somewhat small lilacs. On these types, just deadheading is needed in terms of pruning. You can prune some of the older stems as the plants get older to make place for younger, more robust stems. In contrast to regular lilacs, these plants hardly ever spread out of control. They might never need to be entirely regenerated if you only undertake a tiny amount of trimming every few years.
After the blooms have faded, deadheading, another aspect of annual maintenance, should be carried out as soon as feasible. Just above the two new shoots that slant out from the stem that stopped with the old bloom, the base of the old flower cluster should be cut off. The new shoots will develop throughout the course of the summer, produce flower buds, and culminate in a cluster of flowers the following spring. While not as crucial as the annual thinning, eliminating the old blossoms enables the plant to focus more of its energy on developing robust branches and flower buds. In June, I deadhead and thin my plants as needed.
While performing this yearly maintenance, I occasionally come upon a young, robust shoot that may be getting too tall but is still a good, productive stem and is a candidate for tipping off. I cut the wasted flower’s entire top stem back to one or two side shoots at the desired height rather of just cutting it off at the base. The side shoots that are now near the top of the bush are encouraged to grow vigorously and develop flower buds for the following year by this cut, which also aids in shrinking the shrub.
My own old, overgrown lilacs need more severe pruning. I went outside in the early spring before growth got going to get a good look at the bush. I looked to see if the plant had been grafted before I began chopping. I immediately cut it down to the ground as it hadn’t (for a grafted plant, see the panel below). I recognized that this drastic trimming would result in the plant losing part of its aesthetic appeal for a few years because lilacs bloom on the growth from the previous season. However, I was also aware that the reward—more blossoms and a stronger plant—would be worthwhile.
It’s crucial to nourish the plant after rejuvenation pruning with compost, composted manure, or a balanced chemical fertilizer and to make sure the soil pH is close to neutral, which lilacs appreciate. In the upcoming years, these supplements and some high-quality mulch will help to encourage vigorous new growth and enhanced flowering.
Has your lilac been grafted?
If your lilac has been grafted, check it out before you start making cuts to the stems. Grafting is a method of plant multiplication in which the scion, or branch, of one species is joined to the rootstock, or stem, of another species. This is typically done to enhance a plant’s look or traits. A graft union, where the cultivar’s scion wood joins the rootstock several inches above ground level, should be obvious. An apparent change in the bark from the rootstock to the scion’s bark, as well as a little swelling at the graft union, are things to watch for. If your plant has been grafted, all of your cuttings must be made above the graft union, and you must prevent shoots from the rootstock from developing into new flowering stems. Flowers of the desired shape or color will not be produced by shoots that emerge from the rootstock.
Why don’t lilacs bloom each year?
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.
Does Miracle Grow benefit lilac plants?
When the lilacs begin to blossom, it is a solid indicator that spring has arrived for good. While many people only have a limited knowledge of common lilac (also known as French lilac) shrubs that can reach a height of 15 feet or more, there are now a lot more options available than there were fifty years ago. Some varieties that rebloom enhance the garden’s appeal the entire growing season.
How to Choose Lilacs
The common lilac is what you will most likely find when you go plant shopping. This traditional plant comes in a variety of cultivars and variations, each of which yields fragrant spring flowers in pink, purple, white, or even combinations of those hues. Common lilacs are typically the most fragrant variety of lilac and can grow to be rangy and large.
Rebloomers have arrived in the garden center thanks to recent introductions of hybrids between the common lilac and other shrub-type lilacs. Some of these newer varieties are a bit less fragrant, but they’re smaller, bloom more than once during the growing season, and tend to have fewer problems with powdery mildew.
The tree lilac is another common variety of lilac. It can grow to a height of around 20 feet and blooms with cream-colored flowers in the middle of the summer. Though it doesn’t require much trimming, keep in mind that the tree lilac is a tree, not a shrub.
Where to Plant Lilacs
Lilacs should be planted in full light (at least 6 to 8 hours per day), as too much shadow will prevent them from blooming. Lilacs also prefer moist, well-drained soil that is slightly alkaline.
When to Plant Lilacs
Before the ground freezes in the late fall is the ideal time to plant lilacs. After the earth thaws in the early spring, that is the next ideal period to plant. Lilacs will likely need to be planted as soon as you can locate them at the garden center, which is great; if you choose to do so during a warmer season, they might require additional watering.
How to Prepare the Soil for Planting Lilacs
A soil test should be performed prior to planting since lilacs thrive in slightly alkaline (6.5 to 7.0 pH), moist, well-drained soil that is high in organic matter. Lime must be added to raise the pH if it is below 5.5. It’s time to get the soil ready when you’ve obtained the ideal pH. Improve individual planting holes by mixing Miracle-Gro Garden Soil for Trees & Shrubs in a 50:50 ratio with the natural soil to give lilacs a nutrient-rich start. Iron and phosphorus are also present in this garden soil to promote root development and ward off leaf fading.
Which month should lilac bushes be pruned?
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.