How and When to Prune a Lilac Bush

The Lilac bush (Syringa vulgaris) is a perennial ornamental plant native to Europe and Asia. It is known for its bell-shaped flowers, which are usually purple, although they can also be pink, white, or blue. The flowers appear in clusters during spring and summer and have a sweet and pleasant aroma. Learn all about how and when to prune lilac bush in this article.

Lilac bush can reach a height of 20 to 23 ft (6 to 7 meters) and is commonly used as a hedge plant or create a background in flower gardens. It is a hardy, easy-to-grow plant that requires little attention and can thrive in a variety of growing conditions.

When to Prune a Lilac Bush

It is important to know when to prune lilac bushes to ensure they grow strong and bloom to their full potential. Many lilacs do not need pruning until they reach a height of 6 to 8 ft (2 to 2.5 meters).

The ideal time to prune these bushes is just after they have finished blooming, as this allows the new shoots time to grow and mature for the next blooming season. If pruned too late, the young developing shoots may die.

Tools for Pruning Lilac Bush

The tools required for lilac pruning are simple, with good pruning shears and along with safety equipment that is never superfluous (goggles, gloves, boots, among others).

In case you have decided not to have a shrub but a lilac tree, pruning may require other equipment, such as a saw for thicker branches or a height pruner if the tree is very tall.

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How to Prune a Lilac Bush

To prune a lilac bush the first thing you must know is the type of pruning you want to do, for which you must consider the stage of development in which the plant is. A young lilac bush cannot be pruned in the same way as an adult lilac bush.

how to prune a lilac bush
How and When to Prune a Lilac Bush? Pruning an adult lilac is not the same as pruning a young lilac.

How To Prune a Young Lilac Bush

As we have already mentioned, pruning a young lilac bush is not the same as pruning an adult lilac bush. But When is a lilac bush considered to be young? The answer is relative, since depending on factors such as climate, area, or variety, trees age more or less quickly. To be more specific, we can say that a lilac bush reaches maturity between 5 and 10 years old.

Pruning during this period of growth should be oriented to determine the main structure on which the bush will grow. Let’s see the types of pruning you should do in the development stage.

Formation Pruning of Lilacs

This type of lilac formation pruning consists of directing the growth of the plant, it is advisable to use guides to help achieve the desired structure, these can be 3.2 ft (1 m) to help hold the plant and cut the lower branches.

To perform the lilac formation pruning you must follow these steps:

In the 1st year, all branches of the lilac should be cut back. In this way, lower branches will sprout.

During the second year, the main branches should be cut back a little, to 2/3 of their length. The branches that sprout from the lower half of the trunk should be removed, and the rest should be left.

In the 3rd year, you will trim the main branches to 2/3 of their length, and remove the branches that are growing inwards towards the top of the tree.

How to Prune Lilac Bush Step by Step

Pruning lilacs is easy as long as you are careful not to prune them too late in the season and avoid cutting branches that may develop into flower buds in the future. These buds can be identified as two buds emerging from the stem.

Removing dead flowers down to the first pair of leaves below them will improve next year’s bloom and help keep tree size within limits.

By removing dead flowers, you will immediately rejuvenate the tree, as well as avoid accidentally cutting off buds that will form for the next blooming season. These buds form after the previous year’s flowers have finished blooming.

It is important to remove shoots growing on the stem or at the base of the tree to maintain its aesthetic appearance and prevent them from taking over. If your lilac tree has been grafted, the shoots below the grafting point will likely compete with the main plant. Therefore, they need to be removed as soon as they are detected to prevent them from affecting the growth of the tree.

If your lilac tree is not grafted and the suckers are growing from the base of the tree, they can be carefully removed. If these suckers still have their roots, they can be transplanted to give you another lilac plant.

Another option is to cut the shoots at the base using strong pruning shears or pruning shears if they are thicker. It is important to avoid cutting the lilac tree itself as this can cause damage.

how to prune lilac bush step by step
How to Prune Lilac Bush? Use sharp, disinfected tools to prune your lilac bush.

Final Conclusions

Newly planted lilac bushes are expected to begin blooming within two to five years. If dead flowers are cut off, this will stimulate the growth of new shoots for next spring. That is why it is important to know how and when to prune a lilac bush correctly.

Not every year your lilac bush will bloom as resplendent as others, but you should not be alarmed because flowering also depends on weather conditions. The most important thing is that the plant is healthy and receives the necessary pruning to develop correctly.

I hope this article about how and when to prune a lilac bush will be useful. Learn more about how to prune Crepe myrtle and when to prune Crepe myrtle trees.

About Henry Morgan

We are the Morgans, Henry, and Julia, both agronomists from the University of Michigan, where we met. We are experts in putting our hands in the soil and developing organic foods and improving production processes for decades. Likewise, we have worked for companies such as Mondelez International, BASF, Monsanto, etc. currently in our role as science writers for TheGardenStyle.com as well as advisors in promoting large scale food growing in urbanized areas. In this website, we share what we are most passionate about, gardening and farming. Enjoy and see real photos on our website.