Lilac is one of the exquisite ornamental trees that bloom magnificently without a cut. Nevertheless, there are important reasons to prune a lilac tree. Sometimes it is even unavoidable to radically rejuvenate a Syringa vulgaris. This green guide explains in detail when and how to do it right. You can find out here under which conditions you can give an old lilac tree new impetus with a rejuvenation cut.

cutting needs

These criteria signal the need for a cut

As long as your lilac is in full bloom every May, pruning will do more harm than good. All lilacs bloom on their two-year-old wood, provided the tree can bud in peace. If the one-year-old shoots fall victim to the scissors, the hope of a lavish bloom is gone.

At least in the first 5 to 7 years, the natural development should not be interfered with with scissors and saws. If the ornamental tree is getting old, the following features signal that a pruning now makes sense.

  • the lilac is getting too big
  • the flowers appear increasingly sparse
  • the bush or crown is bare from the inside
  • the wood loses its compact, dense growth habit and falls apart

If you cultivate lilac bushes as a privacy hedge, annual pruning is mandatory as soon as the plants have reached the desired height. The naturally loose habit will only keep prying eyes away from your property if you trim the hedge regularly.

time for the cut

The best time is after flowering

Does one of the criteria mentioned for a shape and maintenance cut apply to your lilac? Then you will affect the next bloom the least if you prune the shrub immediately after blooming. Choose a mild, overcast and dry day in June. At this time, the one-year-old shoots have not yet formed the buds for next year's flowering, or have only just formed them.

If you only intend to thin out the crown of the lilac tree or the bush, we recommend the leafless time as the time. If a Syringa vulgaris has dropped its leaves in late autumn, you have an excellent view of the framework. This means that you can make an informed decision between November and February as to the extent to which this cut should be made.

Instructions for the cut

Instructions for the right cut

Please have a stable cutting tool ready, as lilac is one of the hardest types of wood. Saws and scissors should not only be sharp, but also disinfected. By rubbing the blades with high-proof alcohol, any pathogens are reliably removed.

This is how the incision runs in an exemplary manner:

  • Cut back all withered flowers down to the first pair of leaves
  • Cut all dead, puny branches down to the trunk
  • Cut off the weaker branches that are too close together or rubbing against each other
  • Prune shoots that are too long by a quarter so that at least 4 eyes remain on the branch
  • apply the scissors a few millimeters above a leaf node or a bud

To continuously rejuvenate a lilac, prune the two oldest branches to 8 inches (20 cm) every 2 to 3 years. In this way, you effectively prevent senescence, so that you never have to radically prune a magnificent lilac tree. It is advisable to clean out the withered flowers from the very first flowering period, so that even a young lilac does not invest any energy reserves in the growth of seed heads. Please always limit the pruning to the leafless area below the withered flowers.

No water shooters

No chance for the water shooters

If you cultivate a grafted lilac tree in your garden, it consists of two segments. A noble lilac with lots of flowers was grafted onto a game base. This method is a double-edged sword. On the one hand scion benefits from the vigor and resistance of the wild rootstock.

On the other hand, wild shoots continuously sprout from the rootstock to overgrow the noble segment. Please remove these water shooters as soon as they catch your eye. Instead of cutting them, tear off shoots that grow steeply upwards with a bold jerk. In this way, no tissue residue remains from which a new water instinct can make its way.

Cut off root shoots

Pinch off root shoots and do not cut

The ungrafted common lilac tends to spread invasively with root suckers. In connection with this propagation tactic, root shoots sprout from its foothills even at a great distance from the tree or shrub. These are not subject to the normal cuts in early summer.

As a rule, they have not reached a conspicuous growth height until autumn. Cutting or tearing it out does not fix the problem. Instead, scoop out the root sucker in question with the spade and dig up the sapling along with its own roots.

Special case taper cut

If not a single shape and maintenance cut is carried out for years or decades, the wood will age noticeably. In view of the tremendous growth potential of a lilac, you should not throw in the towel and consider clearing it. By radically pruning and rejuvenating an old lilac tree or shrub, you can give it a new lease of life. In contrast to the normal topiary, the winter sap dormancy makes sense as an appointment in this case.

How to proceed professionally:

  • choose a frost-free day between November and February
  • Prepare a stable, freshly sharpened saw and anvil pruning shears as tools
  • Cut back the 3 to 4 youngest main shoots to a height of 20 to 30 cm
  • Prune all other old shoots close to the ground or on a branch

With the help of the 3 to 4 leading shoots you build a new framework in the crown and in the bush. In the two following years there are no flowers because the bud-bearing branches have to develop first. Nevertheless, cut off all the stunted new shoots for each main branch in autumn after the rejuvenation cut and only leave the two strongest and best placed side branches.

If necessary, repeat this measure in the autumn of the following year until a harmonious basic structure has developed on the lilac. After the first flowering, the rejuvenation cut then leads to the normal, reserved cut for a Syringa vulgaris.

Category:

Garden plants