Cutting lilacs: when & how to cut back?

With its colorful blooms, the lilac is an eye-catcher in every garden. We show when and how it is best cut to keep it in shape.

The genus of lilacs (Syringa) includes several types. All of them stand out with their colorful and splendid blooms in May or June in the home garden. But no matter whether it is the famous common lilac (Syringa vulgaris) or a dwarf lilac (Syringa meyeri 'Palibin') - they should all be cut regularly so that they can adorn the garden in a beautiful shape for as long as possible.

When and how to cut lilacs?

When it comes to the correct pruning of a tree or shrub, the same questions always arise:

• When is the right time?
• Which branches need to be cut?
• How far do I have to / may I cut back?

Of course, these questions also arise when cutting the lilac - and rightly so. Because the lilac can, depending on how radically cut back is to be, step a little out of line. When cutting the lilac, you have to distinguish between different types of cut:

• Maintenance pruning (following the flowering of the lilac)
• Radical cut for rejuvenation (in autumn or spring)
• Parenting cut for young lilacs (in autumn or spring)

In the following we will take a closer look at the different shapes of the cut and show when which option is the best for the lilac.

Conservation pruning - pruning dwarf lilac

The so-called maintenance pruning is the optimal solution to keep a dwarf lilac in shape. But even with an ordinary lilac, which at 6 m in height can grow up to 4 m higher than a dwarf lilac, this form of pruning should be preferred to a radical pruning. The following should be known about the conservation pruning in lilacs:

• Time: from mid / end of June when the flowers have faded
• Snap out the flowers as far down as possible.
• Caution: Do not cut back too far down into the new shoots. On these branches there are already buds with flower systems for the next year. Therefore, at least three eyes should remain on the new shoot. If the cut is too deep, the lilac may be able to grow in the next year. not bloom.
• Occasionally prune branches further to get a shape. Then you can cut back into the two / three year old wood.
• The further pruning of the branches rotates, so that different branches are cut back from year to year.

Thanks to the regular maintenance pruning following the flowering of the lilac, you keep it in shape and do not have to do without the beautiful, splendid bloom.

Radically cut and rejuvenate lilacs

If the beloved lilac has been neglected in recent years, it can lose its bushy shape over time. Weather-related breakage of branches can also disfigure the beloved lilac. A radical cut back then seems to be the last solution. There are two different options here, but they are not entirely without risk.

• Cut all the branches far back into the old wood at once

Of course, you can cut all the branches of the lilac at once, deep into the old wood. This takes place in early spring before the new lilac shoots. However, there is then the risk that the lilac will no longer sprout from the old wood, but will merely form new root shoots. First of all, after a radical cut back into the old wood, these must be removed in any case. By removing the root saplings, the energy is pushed into the old wood of the lilac. This preserves the possibility that any remaining dormant buds will sprout again.

• Divide the radical cut over several years

The radical cutback can also be spread over several years. Then the branches are shortened within two or three consecutive years. This is also done in early spring. On the one hand, the lilacs bloom at least partially despite radical pruning. On the other hand, the remaining, leafy branches ensure that the cell sap is pressed into the crown. So it is more likely to sprout the sleeping eyes in the woody parts of the lilac and that Sprouting of root shoots is not provoked as strongly as with radical pruning in one Year.

No matter whether all at once or over several years - it is important to always remove the unwanted root saplings. They steal the buds that should actually sprout after pruning, namely the energy. In addition, the newly emerging branches should be shortened again in the following years and only three to four strong secondary branches per main branch should be left. This thinning after the radical cut is important in order to help the lilac to regain an attractive shape.

Raising young lilacs by cutting

You bought a young lilac when planting in autumn or early spring - then it can certainly grow first, one might think. But that's wrong, because even a young lilac in your own garden needs full attention when it comes to cutting. Pay attention to the following when raising a lilac in the first few years:

• Cut out weak shoots
• Shorten main shoots (one third to one half)
• Repeat several times if necessary
• You may have to do without flowering at first, but the early pruning measures will pay off!

Cut dwarf lilac

Dwarf lilacs remain clearly inferior to common lilacs in terms of growth. Therefore it is usually sufficient for these small specimens if the regular maintenance pruning is carried out. This will keep the dwarf lilac in shape, branch well and always be in bloom.

Lilac care is not just about cutting. That Fertilizing the lilac can provide a greater bloom. You can find out what to watch out for here.

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