How deep are the roots of a lilac tree

How Deep Are Lilac Roots? (Lilac Root System Explained) – LeafyJournal

While growing any plant in the garden or nearby the house, it’s essential to know how deep the root system of that plant for in the ground so that you can be assured that the roots won’t damage your home’s foundation.

And the same concern goes for while growing lilacs too, thus, wanting to know how deep lilac’s roots are might be one of your common queries. So, let’s quickly find out the answer. 

How Deep Are Lilac Roots?

The root system of lilacs is not deep, rather it is a shallow root system, therefore, the roots of lilacs tend to remain at top of the soil surface and go as deep as 18”-24” in the soil. However, due to the natural tendency of lilacs to settle in an area, the roots might spread out a little bit.

Table of Contents

You will find quite a lot of lilac varieties out there such as Korean lilac, Japanese tree lilac, Miss Kim lilac, Texas lilac tree, common lilac, lilac bushes, and so on.

Thus, while thinking of growing any of these lilac varieties, wanting to know how deep each of their roots goes in the soil is natural. Therefore, take a look at the individual explanations added below regarding these lilac types. 

Lilac Bush Roots:

In general, the roots of a lilac bush will go deep only about 18”-24” deep in the soil, it’s naturally supposed to stay concentrated on top of the soil.

And the reason behind it is that lilac bushes have a shallow root system that doesn’t go deeper into the ground. However, the roots may spread over time a little bit and it’s considered natural. 

Common Lilac Roots:

Common lilacs are one of the lilac bush varieties and it falls in the category of the large and upright lilac bushes.

Hence, the common lilacs are lilac bushes as well, therefore, the root system of common lilacs is shallow too. This means the common lilac roots are deep as 18-24” in the soil. 

Japanese Tree Lilac Roots:

Lilac trees are said to have deep roots, however, whether it’s a lilac bush or lilac tree, most of the time even the roots of a lilac tree are seen to go as deep as 18-24” in the topsoil.

Thereby, it can be said that the Japanese lilac tree roots will be stay concentrated at a depth of 18-24” in the soil. 

Miss Kim Lilac Roots:

Miss Kim lilacs are lilac shrubs, and it’s stated that lilac bush and shrub roots regardless of the variety are deep as much as 18-24” only which remains concentrated on the topsoil surface.

However, the roots of Miss Kim lilac will spread quite much in diameter. 

Korean Lilac Roots:

Korean lilacs are actually called dwarf Korean lilac, and as the name implies, these dwarf Korean lilacs grow up to only 5-6’ upon maturing. As a result, their root system is shallow as well and is about 18-24” deep. 

Texas Lilac Tree Roots:

Texas lilacs aka Chaste lilac tress are shrub plants which means like other shrub varieties of lilacs, their roots don’t go deep as well in the ground and stay only up to 18-24” on the topsoil surface. 

Are Lilac Roots Deep Or Shallow?

The root system of lilac bushes and shrubs is shallow. As a result, if you have a shallow foundation and have planted lilacs around your home or in the yard in front, the roots of a lilac bush or shrub will go down to the base of the shallow foundation only, nothing more. 

But if there’s a deep foundation, don’t worry at all. The shallow root system of lilac won’t reach that deep, so there aren’t much chances of any damage. 

However, some sources stated that the lilac tree root system is deep and extensive, and the roots can go down up to a meter or more in the soil. Check the depth of lilac shrubs, bushes, and trees’ roots before planting. 

Do Lilac Trees Have Invasive Roots?

Lilac trees don’t have invasive roots, which means the roots of lilacs aren’t likely to grow in the ground to find nutrients and water while making pathways under driveways, water lines, building foundations, walkways, and sewer pipes, etc. 

However, lilac roots are not acknowledged as invasive roots only when enough room has been left between the lilac tree/shrub/bush and the building’s foundation/driveway/water lines, etc. Otherwise, lilac roots sometimes can be invasive. 

So leave at least 12 feet of space between the lilac shrub/tree/bush and the structure to prevent any invasion of lilac roots. 

How Much Room Do Lilac Roots Need?

If you are planning a lilac seedling in the ground then the roots of the seedlings will be needing at least 2 inches to 3 inches more space in the ground than where they grew up originally. 

Also, remember that even if lilac bushes/trees/shrubs’ roots aren’t assumed as the invasive root system, the roots sometimes can be invasive.

So to avoid such an unpleasant situation, you must plant a lilac at least 12 feet (4 meters) away from your home’s foundation/driveway/pipe lines/sewage line, etc.

This suggested space between a lilac bush/tree and a structure is sufficient to prevent the risk of structural damage. 

What Kind Of Root System Does A Lilac Bush Have? 

The root system of lilac bushes is a shallow root system, which means the roots of lilac bushes don’t go too deep into the ground, rather the roots remain concentrated only up to the topsoil surface.

Therefore, you will notice a lilac bush’s roots reach deep into the ground up to 18-24” only. 

Also, lilac bushes are most likely to have an invasive root system as well, as a result, there are almost zero chances that any structure such as a house’s foundation, driveway, sewage line, or anything would be damaged by a lilac bush’s roots.

But in this case, you must plant the lilac bush at 12 feet distance from the structure to avoid damage. 

Is It Difficult To Dig Up A Lilac Tree? 

The difficulty level of dogging up a lilac tree depends on the size of the tree and the soil.

If you are trying to dig up a large and matured lilac tree then it can be really difficult that you might need extra people to help you in digging and a vehicle to pull the tree out of the ground. 

But if it’s not a big and matured lilac tree then you can expect to dig down around the lilac tree alone and putting less effort.

Also, if the lilac tree is planted in clay-like or hardpacked soil then it surely would be difficult to dig up a lilac tree. 

How Do I Dig Up A Lilac Bush? 

Well, digging up a lilac bush might seem a little difficult if you are going to dig up a lilac bush for the first time. Therefore, to make the process easy for you, a step-by-step guide is added below.

Water The Ground: 

Before you dig the lilac bush, you have to water the nearby ground around the lilac bush thoroughly so that water helps the soil in the ground to loosen up completely.

It’s easier to dig deep in a loosened up soil, rather than a hard soil because you will be able to dig and pull the lilac bush will less effort from the ground. 

Dig Down From All Sides: 

Next, you will be needing a shovel and a hoe, use that shovel and the hoe for digging down the lilac bush from all the sides and keep removing as much dirt and soil as possible from the hole you created by digging down.

And you must keep digging down until you have reached the foot of the rootball, then gradually free as much rootball as possible.

Pull Out The Rootball: 

Now at the very last step, again use the shovel and slowly pull out the whole rootball from the ground, and while doing so use pruning shears for cutting the extended roots that have crossed the anticipated rootball diameter. And brush dirt from the bare roots using your hands.

If the lilac bush is a young one, after digging down from all sides, you can pull the bush out by hand. 

However, if the lilac bush is a strong and old one, you better use a tractor for pulling out the lilac bush.

After digging down from all sides, tie a rope around the lilac bush’s base and keep adding tension to it through the tractor until the rootball is completely pulled out.

Final Thoughts 

Whether be it a lilac shrub or bush, the root system of lilac is shallow, thus, the roots of lilacs don’t go too deep down in the ground. So, regardless of the lilac variety, the root system of lilacs is 18-24” deep into the soil. But the roots can spread much in diameter to settle down the tree.

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varieties, planting rules, fertilizer, shaping and pruning

A worthy decoration of any garden is a blooming and fragrant lilac bush.

Common lilac (Syringa vulgaris), which will be discussed today, comes from the mountain slopes of the Balkans and the Carpathians. It has become a favorite plant in France, Norway, Sweden, and, of course, in Russia. Due to its unpretentiousness and frost resistance, this lilac has taken root even on the Solovetsky Islands in the White Sea. And today she is quite capable of decorating any garden.

Lilac in May

On the garden lawn, one bush “singles” wonderfully, a small group of varieties of different colors, shapes and sizes also looks great (for example, this combination: low white “Joan of Arc” , columnar "Eduard Harding" with narrow reddish-purple racemes and medium-sized "Belle de Nancy" - she has double bluish flowers). Lilac, planted along the path, can form a wonderful alley. On the site, lilac landings will help hide objects that are not intended for public viewing.

This mountain slope plant does not like to be in the shade and therefore requires a fairly large area in a well-lit area. Her other requirements: the soil is neutral or slightly alkaline, the absence of closely standing groundwater. Low, swampy or temporarily flooded areas are not for her. She will still tolerate drought, but she dies from waterlogging. Lilac grows best on light and medium loams with a high humus content.

The lilac has only one whim: it can't stand the neighborhood with lilies of the valley either on the plot or in a vase.

Selection of seedlings

What is important to know when buying lilac seedlings?

Varietal lilac is propagated only vegetatively: by rooting cuttings, layering or grafting. Be sure to find out which seedling you are offered: own-rooted or grafted.

In the first case, you get an "eternal" plant. With proper planting and care, it will grow in one place for decades. If for some reason the aerial part is damaged, a new one will grow from the root shoots. Old bushes of such lilacs can be rejuvenated by pruning "on a stump", without risking losing the variety.

When buying a grafted seedling, be sure to find out what kind of plant is used as a rootstock. If these are seedlings of common lilac, your bush will also live for a long time. But you will have to constantly fight with wild root shoots. If privet or Hungarian lilac served as a stock, there will be less shoots, but the varietal plant will not live long: after 10 years, the scion will either break off or dry up. Therefore, it is desirable to transfer such a seedling to its own roots.

To do this, it is planted obliquely, deepened. The stem is pulled below the graft with copper wire 3 turns, forcing the graft to give roots in order to obtain food on its own. To speed up their appearance, grooves are made on the bark. If the variety you bought is easily cut, then the seedling will easily go to its own roots.

Common lilacs are grown from seeds. They do not fully reproduce the qualities of the parent variety. But if you have the space, time and patience, wait for the seedlings to bloom. They will bloom in five years. Among them may be plants that are superior in beauty to their parents. In addition, cuttings or buds of any variety you like can be grafted onto seedlings. Seedlings can also be useful for creating a hedge (for example, if your house is located near the road). "Wild" lilac will hold back noise and dust, and will not suffer from them as well as varietal.

Planting instructions

Lilac can be planted in early spring or autumn, just like ordinary garden plants. But it is better to do this at the end of July-beginning of August, after the end of shoot growth.

The root system of lilac is mainly located in the surface layer of the soil, so it is planted in holes that are not too deep. The roots are covered with an earthen mixture of humus, compost, peat, soil with the addition of superphosphate, potassium sulfate, ash and limestone flour. The root neck must not be covered with earth. The lilac develops well and blooms if its root collar is 2–3 or more centimeters above the soil level. It should be borne in mind that when planting a plant and watering it, loose soil gives a draft of 2–3 centimeters.

Seedlings from 1 to 7 years old and even older can serve as planting material. Before planting, excessively long roots are shortened and diseased and damaged ones are cut to a healthy place. Adult plants are usually planted with a clod of earth, with as little damage to the root system as possible.

Before planting, deep tillage (40–60 cm) is carried out with the application of organic fertilizers (humus, compost). For any improvement in soil properties and its fertility, lilac responds with increased growth of shoots and an increase in flowering. Lilacs are planted at a distance between rows of 3–4 meters and between plants in a row of 2. 5 meters.

Feed, but do not overfeed

In the first year after planting in autumn or spring, seedlings do not give full growth and normal leaf size. Forcing growth with increased watering or top dressing is detrimental. Plants, recovering from transplantation, restoring the root system, will give good growth next year.

Proper care consists in moderate fertilization, loosening, especially after rains and watering. In spring and in the first half of summer, loosening is repeated several times, weeds are removed with roots. In dry weather, especially on sandy soils, watering will bring undoubted benefits. Loosening the soil and watering at the end of July is stopped, since by this time the growth of lilacs ends, flower buds are laid on the branches. If loosening and especially watering is continued, the plants may resume growth, and the shoots will not mature.

When feeding a bush, do not get carried away with nitrogen fertilizers: lilac will bloom worse and will not tolerate winter well. It is enough to apply a complex fertilizer in the spring (for example, "Health Turbo Universal", containing all the necessary substances and guaranteeing high efficiency of use) and after flowering potash with phosphorus. Enhances the growth of shoots and improves the color of flowers by adding manganese, boron and other trace elements to the soil (in very small doses).

In autumn, the soil around the bushes is dug up: near the root neck to a depth of no more than 4–6 cm, as you move away from it, the depth is increased to 10–15 cm. - two handfuls of superphosphate.

Shaping and pruning

Annual pruning is carried out to remove crown thickening, diseased and ugly shoots. Pruning is carried out in early spring, before the awakening of the kidneys, as in other garden shrubs and trees.

Will the lilac become a bush, tree or hedge, depending on your wishes and the appropriate shaping pruning. To grow a hedge, remove only dried or damaged branches. We want to get a tree with an umbrella-shaped crown - we remove the root shoots and lower shoots from the strongest trunks. We want a bush - we do not allow it to thicken, we remove the weak shoots growing inside the crown.

(However, the appearance of the plant is largely determined by the variety. If we want to have a low bush with flowers at eye level, so that we can come up and inhale their aroma, we need to purchase the appropriate varieties (for example, Monique Lemoine, Memory of Kolesnikov "," Memory of Vekhove ".

Lilac flower buds are formed on annual shoots. It is often advised to cut faded brushes to improve flowering next year. But keep in mind that this must be done very carefully so as not to damage the nearby with them shoots on which flower buds are laid.0003

- I have been forcing tulips on the window by March 8 for more than one year. And what other flowers can you get at home when it's snowing outside? asks Ekaterina Mityurina from the Perm region.

— Lilacs are easy to winter forcing. If you cut off several branches with flower buds in early February, then by Women's Day you can get blooming lilacs. The forcing process takes about 4 weeks and does not require much hassle, you just need to change the water daily and update the cuts of the branches.

For cutting, choose strong branches with large developed buds. Keep in mind that during the entire period of forcing, you will have to cut the branches daily, so long branches with a flat bottom are more suitable for our purpose.

It is recommended that when bringing branches into the house, first put them in cold water so that the buds are completely covered with water, and leave for several hours, then the branches will gradually warm up.

We fill a convenient deep vessel with settled water at room temperature. We make an oblique cut with a sharp knife and immediately lower the branches into the water - by about 20 cm. (You can prepare a special solution: per liter of water - a tablet of acetylsalicylic acid and 1.5 teaspoons of sugar. According to experts, sugar improves the coloring of flowers and their size. A week after the start of distillation, the solution is replaced with plain water with the addition of acetylsalicylic acid - an aspirin tablet will be enough).

Spray the buds thoroughly regularly. To maintain constant humidity, the branches can be covered with a film. The air temperature is about +15…+20˚С. At higher temperatures, the flowers are less colored and often dry out. The place where the buds will bloom should be well lit: the branches should “believe” that the spring sun warms them. Every day or two, renew the cut and change the water (solution), spray as needed. After a while, leaves will bloom on the branches, and then the first buds will appear. The matter is simple, and the result is amazing: the fragrance of lilacs in March!

Lilac - planting and care

Photo from the author's nursery.

Lilac is always beautiful, no doubt, but it is the attentive approach to the agricultural technology of this crop that allows the gardener to get the maximum decorative effect. So, first things first.

Choosing a planting site

The planting site for lilac should be free from perennial weeds, well lit by the sun, as the culture is photophilous, and there should not be stagnation of ground and melt water in spring or rainwater in autumn. The fact is that the roots of lilacs die during flooding, and then the aerial part of the plant dies, partially or completely. In damp areas, lilacs are planted on artificial mounds, the lower part of which is drainage from crushed stone, and the upper part is fertile soil, but in this case plant care should be especially thorough.

When choosing planting material, it is better to give preference to own-rooted lilacs in a container. Own-rooted plants are more durable than grafted ones. A closed root system allows planting at any time convenient for the gardener. The size of the plant in the container, of course, matters: it is optimal to take lilacs for planting in containers from 2 to 12 liters. If the lilac is larger, then its price and care efforts increase dramatically. We understand that a large seedling will bloom faster, and maybe already blooming, but the more powerful the plant, the more and more often it requires watering in the first year or two after planting. And lilacs in small pots of 0.5-1.5 liters, as a rule, before planting in a permanent place, require growing up in a “school” for two to three years.

Soil preparation

Lilac soil should ideally be fertile and loose, neutral or slightly alkaline. Soil deficiencies can be compensated for by preparing the planting pit. If the soil is heavy clay, then you need to add a mixture of coarse sand, humus and peat in a ratio of 1: 2: 4, if sandy, then the best option is to add chernozem soil or clay and humus at the same time, and on acidic soils add another one or two handfuls slaked lime. Digging a planting hole. Its size depends on the volume of the root system of the seedling. The main thing is that the distance from the root ball to the walls of the pit should be at least 20 cm. If the soil has imperfections, then we mix it with fertility-improving components - this mixture will be used to fill the pit when planting. Humus, as you know, is rich in substances for plant nutrition, and if there is a lot of it in the mixture, then when planting mineral fertilizers, it is better to apply slow-acting, one or two handfuls to the bottom of the pit. By the way, it should be remembered that humus cannot be replaced with fresh manure. Manure during planting and for feeding lilacs is undesirable for a number of reasons, but this is already a topic for a separate article. Another common mistake is that on heavy clay soils, many make a large planting hole 1x1x1m, filling it with loose soil (for good reasons). As a result, after planting, the soil settles for several years and a sort of drainage well is obtained, in which the lilac dies from flooding, as a rule, in the spring, because the melt water "goes" to where the soil is lower and looser. Therefore, always take the original soil on your site as the basis for filling the planting hole.


It is more convenient to plant lilac plants together. One gardener lowers the root part of the plant into the pit and holds it by the stem so that the root neck is at ground level, and a colleague pours soil into the pit. Then the soil in the hole is tightly trampled around the plant. Next, the plant should be watered abundantly, using at least a bucket of water. This moment is very important, since water displaces air, invisible voids disappear and there is a tight contact of the roots with the poured soil. When the water is absorbed, the remaining soil is poured into the trunk circle, and neutralized high-moor peat should be poured on top with a layer of 5-6 cm as mulch. With mulch, there is no need for weeding and loosening - the mulch will do it for you. In subsequent years, fertilizing is best done in the spring. The easiest option is to add a bucket of humus mixed with a liter of wood ash to the trunk circle (under mulch). Do not overfeed, and the plant will receive tangible support.


In the first year after planting, lilac should be watered as needed, but most importantly - plentifully, this contributes to the growth of roots in depth. Lilac is a drought-resistant crop, and excessive "gulf" of the plant, as mentioned earlier, can lead to the death of the plant. The gardener should be attentive to lilacs and avoid extremes - do not flood, but do not dry.

Bush formation

There are two approaches to this issue. The first is that nature will do everything by itself, pruning, if needed, is only for sanitary purposes. The second - you should actively form the plant in the first 3-4 years after planting in a permanent place. Going through the formation of a bush, the gardener mainly solves two problems - to make the bush lush with a large number of axial branches or to give it an unusual shape compared to the natural one, for example, a standard one. It is no secret that many lilac varieties naturally have a rare, ankle-length, tall bush, but pruning can correct these shortcomings. To get a lush bush, you need to make the plant actively branch. To do this, next after planting in early spring, before the buds open, we shorten the annual shoots with a pruner by one third, and repeat this pruning for several years until the bush density we need is reached. Since the flower buds of lilacs are located at the ends of annual shoots, and lilacs will not bloom after pruning, everyone makes their own choice: either the lush flowering of the formed plant “later”, or rare - “now”. During the season, when forming a bush, weak, twisted shoots should be removed, as well as those growing inside the bush, and weaker ones from the branches of competitors. It also happens that the plant is small, but already blooms and the inflorescence can be quite large. It bends a thin stalk like a sail in the wind, and when damp after rain, it bends the stalk to the ground. In this case, unfortunately, it is better to remove the inflorescences in order to enable the plant to "take the force", then it will please you in the future. It should also be remembered that at the end of flowering, wilted and faded inflorescences must be cut off immediately, since a lot of vitality is spent on the formation of seeds, and the plant will bloom less next year, and the very appearance of last year's panicles of gray-brown color among the new May inflorescences is not aesthetic.

Prevention of diseases

A lot has been written about possible lilac diseases, but everything is not so scary. A favorable environment for fungi and bacteria is excessive thickening of the bushes, so we do not thicken the plantings, but for prevention every spring we spray the plants with copper oxychloride (according to the manufacturer's instructions) until the buds open. It should be noted that with high agricultural technology of lilac, diseases are extremely rare, because, as a rule, weakened plants get sick.

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