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.
How much may a lilac shrub 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.
What time of year should a lilac bush be pruned?
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 revitalised 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 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 colours. Winter burn may be caused by the reflection. Cover the plant’s base with 3 to 4 inches of mulch to help minimise 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.
For the winter, do you trim back lilac bushes?
Lilacs should be clipped no later than two weeks after they have finished blooming in the spring, if you’re wondering when to do it. Since lilac bushes start to form buds in the summer and those buds last through the winter in preparation for the next spring’s bloom, cutting at any other time of the year would be a mistake.
Even though you’ll be removing prospective flowers, you can prune in the late winter if you’d rather do it while the plant isn’t covered in foliage. To learn how to prune a lilac shrub, follow the instructions below, regardless of the cutting method you decide on.
What distinguishes a lilac bush from a lilac tree?
Lilac bushes (also known as shrubs) are characterised 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 neighbourhood garden centre 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 require sunlight to bloom well.
How can an aged lilac bush be revived?
The common purple lilac is a hardy, dependable shrub that can grow up to 20 feet tall. Unfortunately, the lower, shady sections of lilac shrubs typically lose their leaves as they get older. Large, overgrown specimens as a result are frequently leggy and ugly. Pruning can restore or rejuvenate old, neglected lilacs. Home gardeners have two alternative pruning techniques to pick from.
Cutting the entire plant back to within 6 to 8 inches of the ground in late winter is one method of renewing a huge, overgrown lilac (March or early April). A significant number of shoots will sprout during the growth season as a result of this aggressive pruning. Select a few sturdy, robust shoots to construct the shrub’s framework, keeping a few of them, and cut off all the others at ground level in the late winter of the next year. To promote branching, head (clip) back the retained shoots to just above a bud.
Cutting back the overgrown shrubs over a three-year period is a second method for pruning mature lilacs. In late January, start the process by digging up and removing one-third of the big, old stems. The following year, trim out half of the remaining old stems (again in late winter). Additionally, trim out some of the recent growth. Keep a few healthy stems that are evenly spaced apart and cut off the rest. In the third year’s late winter, completely remove all of the old wood. It is also necessary to thin the fresh shoots more. This pruning technique should enable you to take pleasure in blossoms every spring because lilac wood must be three years or older before it blooms.
Within a few years, with the right pruning, an old, overgrown lilac can be converted into a robust, appealing shrub. Pruning should be a frequent component of the lilacs’ management regimen after they have been revived. By cutting a few of the oldest branches every three to five years, the shrub can be kept strong and healthy.
(This article, which first published in the Sunday edition of the Lincoln Journal Star Newspaper in February 2005, has since been amended. Consult the Terms of Use for details on how to copy this content and use any images or visuals.)
What height are ideal lilacs?
Who doesn’t like lilacs’ stunning appearance and strong scent? These traditional favourites make lovely accents to almost any landscape. However, to maintain lilacs healthy and looking their best, regular trimming is essential. Although there are lesser types that grow to a height of 10 to 15 feet (3 to 4.5 metres), many lilacs can grow as tall as 30 feet (9 metres) if they aren’t regularly pruned. Regular pruning prevents lilac trees from growing too big and becoming difficult to manage.
Should lilacs be Deadheaded?
The removal of spent flowers to encourage new blooming—deadheading—is a crucial part of lilac maintenance. Lilacs should be deadheaded as soon as the flowering is finished to allow the plants to grow robust, healthy buds that will flower vivaciously the following year. According to the University of Minnesota Extension, you can use a hand pruner, but larger plants could require a hedge trimmer. Only the dead blossom should be removed; the plant should still have two leaves.
According to the Chicago Botanic Garden, you should prune lilacs at the same time as you deadhead them since they set the blossoms for the following year quickly after flowering. By doing this, you can prevent damaging or removing the developing buds. Three to four years after planting, you should start pruning lilacs. It might be necessary to trim back overgrown lilacs to just a few inches above the ground. Winter is the ideal time to complete this. In this instance, it will take the shrub one or two growing seasons to start blooming once more.
Around lilacs, should you use mulch?
Lilac Planting and Propagation Basics In regions with hard winters or on places exposed to brisk winds, spring planting is advised. The strongest plant for surviving a harsh winter will be produced by early spring planting and good care during the first growing season. In regions with moderate winters, fall planting (August 15–October 15), might be taken into consideration. Lilac planting in the fall will provide additional root establishment to support growth in the plant’s top. Lilac roots will continue to grow until the ground is frozen.
The soil quality will determine how much effort is needed to grow a lilac. A good idea is to have the soil tested so that the entire area may be changed before planting if the pH or fertility levels are low. Treating the entire area is always preferable to attempting to change merely the planting hole. The latter may result in a “pot” situation when roots circle the hole and ultimately suffocate the victim.
Additionally, area-based management of drainage is ideal. Pure clay “pot holes” will fill with water and drown the plant placed inside of them. Since lilacs are delicate to damp soils, they require proper drainage in order to thrive. Dig a hole that will accept the roots without bending or breaking them before you actually plant the tree. If an organic fertiliser is used, such as bone meal, it should be incorporated into the planting soil because surface applications very little affect the roots. Work the topsoil around the roots of the plant to the same depth at which it grew in its prior location. The graft union, which is situated close to the old soil line if the plant is grafted, ought to be below the soil line. The plant will take longer to grow and the roots may perish from a lack of oxygen if they are planted more than 2 to 3 inches lower than their original position. Fill the hole with water and let it drain after working in the topsoil. This will eliminate air pockets and compact the dirt around the roots. After that, apply more topsoil to the top layer. To ensure that subsequent waterings remain in the root zone, a tiny saucer dam can be built around it. A mulch of straw, bark, or stone placed around the plant will aid in weed control, moisture retention, and the avoidance of frost heaving.
It will take much less time for the freshly planted plant to establish itself if nearby vegetation is kept to a minimum. The battle for water and food will be won by weeds, tall grass, or even lawn grass in close proximity to the newly planted lilac. As a result, the plant will be extremely frail and grow slowly for several years. Around the new lilac, there should be at least one foot of cleared space, but even more is preferable.
The amount of soil moisture during the first growth season is crucial. Even for a little period of time, drought stress will drastically impede the growth of new shoots and delay the establishment of plants. Lilacs take one or two years to begin to grow, and if they are neglected in the first year, this will be considerably more obvious.
In any region without a harsh winter, fall planting is advised. By August, the plant’s top has finished growing and developed dormant winter buds. However, the roots might keep expanding up until the ground freezes. The likelihood of drought conditions is the major issue with fall planting. In New England, summertime moisture is primarily produced by showers that can occur late in the season or bypass a specific area. Dry soil will slow the growth of new roots and, in extreme cases, can kill the plant. A consistent watering schedule will greatly increase the likelihood of a successful fall planting by preventing water stress.
Because there is still plenty of time for root growth, the ideal period in northern New England is from August 15 to September 30. It is possible to plant later, up until October, but the later you plant, the higher the risk of winter kill if the winter is harsh or the snow cover is thin. Plants will be protected in the winter and soil moisture will be retained in the summer by a three-inch layer of wood chips or bark mulch. Mulch prevents grass and weeds from growing yet still permits the lilac plant to flourish.
The planting process is the same whether one is relocating a lilac between locations or purchasing a new balled and burlapped or container-grown plant. Dig a hole with surrounding dirt and use high-quality plants to allow the roots to spread out freely. The sole distinction from planting in the spring is the need for extra caution to avoid drying during or after planting. The family pet can be roasted just as quickly as a recently acquired plant left in a locked car in a parking lot. Additionally, a plant dug from one place and kept in the hot sun without being planted might quickly experience significant root dryness damage. Following planting, watering should be taken into consideration whenever natural rain is insufficient and should continue up until a strong freeze.
Early October is a popular time for planting. In addition to being less busy than in the spring, the weather is typically much more favourable for outdoor activities. Additionally, plants still have their leaves at this time, so the impact of a newly planted plant can be observed right away.
Remember, THE MORE SUN THE BETTER, SO LOCATE AN AREA WITH FULL SUN EXPOSURE WHENEVER POSSIBLE!
Planting by the trench method:
The trench technique of planting can yield good results when there is enough room and a mass planting or hedgerow is needed (see typical below). This process makes it possible to have plenty of enriched soil for healthy plant growth and simple maintenance. Plants spaced 5′ apart with a second alternate row provide good sprouting, which quickly gets rid of grass and weeds. There is little under 8 cubic yards of loam required to create a bed that is 4 feet wide, 2 feet deep, and 25 feet long. Ten plants can be accommodated with this amount. By increasing the width to 6 feet, the planting detail can be changed to utilise 3 rows. The perimeter of the bed should have sod removed to a depth of 3 inches and a width of 1 foot, followed by mulch to decrease competition with grass.
Side view in Figure 1. Plant in two overlapping rows. NOTE: Testing the soil will help identify any nutrients that may or may not be required.