Pruning lilac: when and how do you do it?
With lovely plumes, a sweet scent and beautiful colours, the classic lilac (or Syringa ) fits well in a romantic garden of any size. Is pruning the lilac (tree or shrub) also on your to-do list this spring? By pruning at the right times and in the right ways, you promote healthy growth and flowering in your plant.
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We are talking about the most common lilac shrub here, namely common lilac or Syringa vulgaris . It is best to prune this in late winter or in March to rejuvenate the shrub or tree. After flowering (usually in June) you can remove the flower heads and prune lightly. This will cause the plant to produce plenty of new flower buds for next year. You can read it again below.
In early spring you can apply the rejuvenation pruning . The plant is still dormant and can be pruned well.
The lilac usually blooms around May and June. It is advisable to remove flower heads immediately after they have finished blooming. The energy is then put into creating new flower buds instead of seeds.
During this period it is best to leave the lilac alone. The plant is busy building up reserves for the following year and by pruning it now you are disrupting the plant in that process.
In the fall and early winter, it is best not to prune the lilac, as this can affect the production of flowers and cause you to have no flowers the following year. The best time to prune is in late winter and early spring. The plant can then recover well before the next growing season begins.
With this handy step-by-step plan you can prune a lilac yourself. What you need is a clean and sharp (telescopic or not) branch shears and ditto pruning shears.
Is your Syringa done flowering? Then cut away the wilted flower plumes. Follow the branch with the flower downwards, until you come across leaves. Just above the leaves is the right place to prune. If you don't come across leaves, you can prune the branch with flowers just before the point where it joins a larger branch, as in the photo above.
Cut away water shoots. You can recognize these softer new shoots by the way they grow from the base of the plant, namely straight up. Water shoots will not grow flowers. Prune water shoots back to the place where they meet the main branch. Continue cutting away these new shoots throughout the season, so that the lilac puts all its energy into the healthy branches that can form flowers.
Check for dead or diseased branches, or branches that cross each other. You can remove these completely. Cut away one branch in the case of crossing branches.
Prune healthy branches back by a maximum of one third. Prune just after a bud. A new shoot can grow from there. If you prune regularly, it is even advisable to remove less than a third of the branch. The lilac blooms on one-year-old wood and will not produce flowers the following year if you prune it more severely, but only the year after that.
Do you have a lilac that has grown too big? Or is the plant very spindly with flowers that only emerge far up the branches? Then you can prune the plant back more drastically. This is called rejuvenation pruning. It is best to prune the shrub back severely in the winter, when the plant is dormant. You can prune Syringa vulgaris back to about a meter above the ground. It is good to know that you will not see any flowers in the plant the following year, because the flowering is on one-year-old wood.
Another option is to cut branches over a period of several years, pruning them back to the ground in turn. This way you can enjoy flowers in the remaining branches, but also gradually prune your shrub into shape. Two years after pruning you can enjoy flowers on the pruned branches again.
Pruning a lilac on a trunk (or lilac tree) is done in much the same way as with a lilac bush. Cut away faded flowers to encourage the formation of new flower buds and prevent the plant from putting its energy into producing seeds. Also prune away shoots that are too long and, if necessary, apply some topiary pruning . Also remove water shoots.
If you have an American lilac, it is advisable not to prune it too rigorously, but to keep to a light pruning. With evergreen American lilac species, a heavy pruning can ensure that it no longer grows back well, so be careful with this. If it has really started to proliferate, it is often better to get a new plant.
If necessary, you can prune these species lightly.
- Spring bloomers are lightly pruned after flowering. For those that bloom in the spring. Remove dead wood and remove excess side shoots.
- Late flowering varieties should be pruned in the spring. Remove a third of the woody shoots from last year.
Remove last year's woody stems and do this in early or mid spring, before the plant starts to flower.
- When should I prune which plant?
- What should I pay attention to when pruning?
- The best tips for a blooming garden.
Some lilac varieties, such as the small-flowered lilac ( Syringa microphylla ), even bloom twice a year! In the case of these more frequently flowering varieties, you can cut away the dead flower clusters after the first bloom to make room for new flowers. Otherwise, you do not need to prune this lilac, unless you come across dead or diseased shoots. You can remove these immediately.
Most lilacs ( Syringa vulgaris ) bloom in May or June. The American lilac ( Ceanothus ) also blooms in that period, but sometimes as early as April. The dwarf lilac ( Syringa meyeri ) usually blooms a little later: in June-July. The small-flowered lilac ( Syringa microphylla ) usually blooms in May-June, but can also bloom a second time in August-September. If you cut off the flowers immediately after flowering, the plant will put its energy into making new buds.
After you have pruned the lilac tree, your plant will need little further support. If you notice that the plant is not growing well, you can give it some extra nutrition, such as compost or organic fertilizer . You can also add a layer of mulch . This will protect the soil from drying out and the roots from cold and rain. With this care, you can fully enjoy your lilac again next year!
