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How and when to cut summer lilac: Tips around the butterfly bush care.

Summer lilac is a beautiful shrub , which in summer forms dark purple flowers. Its flower buds are not only pleasing to the eye, but also emit a pleasant fragrance. As long as the site and soil meet its requirements, the shrub requires little care. However, there is one thing that the amateur gardener must not forget: to give it a pruning. We explain how and when you should cut the summer lilac.

1. why you should cut the summer lilac.

butterfly bush cutting when after flowering or in winter

Butterfly bush can not cope without pruning. The plant quickly becomes woody and then stops producing flowers. Similar to most berry bushes, it forms flowers only on new shoots. That is why pruning is essential. When is it done and what should you pay attention to?

1.1 Pruning summer lilacs: The right time is crucial

annual butterfly bush cut or not tips

The right time for pruning is in spring. You can prune your shrub at the end of February – beginning of March, because then there is usually no more permafrost and the plant has enough time until summer to form new shoots. Pruning in the spring can postpone flower formation until the end of summer.

Summer lilac, by the way, is an invasive plant species. It spreads by seed and can crowd out other plants in your home garden. Therefore, it is very important that you remove all seedlings in a timely manner. If you can’t get the plant under control, for example, because you are short on time or simply can’t manage the tedious task, then it’s best to remove it from the garden completely.

1.2 Properly prune summer lilac: Instructions

Summer lilac pruning tips and sketch for proper pruning technique

The butterfly bush is not an evergreen plant. However, it can retain its green foliage if the weather remains relatively mild during the winter months and temperatures do not drop below 0° Celsius. Whether it has green leaves in the spring or not, you should cut it back heavily in mid-February to early March. This will encourage flowering and growth. Do this as follows:

how and when to cut summer lilac tips for amateur gardeners


1. remove all old shoots that produced flowers the previous year.

2. lighten the shrub by pruning too thin and weak canes to ground level.

3. you should also cut competing canes close to the ground. This will help prevent them from forming new shoots in the spring.

Cut all canes that have produced flowers in the previous year. Leave two leaf bases when you do this.

To get the job done quickly, you’ll need the right garden tools. Since the bush has thick branches, it is not always possible to cut them with pruning shears. In this case, the folding saw is a good choice. Do not forget to wear equipment gloves.

Different pruning techniques for each species of summer lilacs

Butterfly bush invasive varieties good or bad for home garden

Of course, pruning techniques differ for different species of summer lilac. For example, the yellow summer lilac is not hardy and can not stay outside in the cold season. In Germany, therefore, it is grown in a tub. In other countries, where it grows in gardens, it is actually cut in May. However, for the tub plant, it is recommended to prune it in February. Of course, then you need to bring the shrub into the greenhouse or unheated room, so that it does not freeze.

The alternate-leaved summer lilac is also an exception. It forms flowers on old canes from the previous year. Therefore, vigorous pruning is out of the question for him. Most amateur gardeners simply cut off the faded shoots and thin it out as needed. In individual cases, for example, if the alternate-leaved summer lilac is heavily woody, pruning at the beginning of spring makes sense.

Very important: after you cut the shrub, you should dispose of the cut branches so that it cannot spread in the garden and in nature.

1.3 Pruning summer lilac: Useful tips

Butterfly bush pruning in the garden instructions for amateur gardeners


In order to enjoy your summer lilac for a long time, you should take into account some basic rules when pruning:

1. prune the shrub annually. In principle, every old shoot that has not been cut off below the leaf base will form new shoots the next year. Thus, the shrub becomes too dense after only a few years. You lose track of it and can’t reach the old shoots to cut them off. Then they begin to lignify, flowering diminishes and the shrub loses its charm. It doesn’t have to be this way: save yourself effort and time and thin out the summer lilac every year.

Cut butterfly bush according to flowering time or not

2. If pruning is done at the wrong time, then the plant may die. Many amateur gardeners commit the mistake of cutting back the shrub after flowering in late summer or autumn. However, the freshly cut back shoots do not have time to recover and may freeze to death during the first frost in October.

3. cut the shoots in the wrong place. Old shoots should be cut on the second eye-mark, thin, diseased or competing branches cut back to ground level. This will help you avoid radical pruning in the future.

Summer lilac cutting tips in spring ideas

4. use the wrong garden tools. Since summer lilacs often become woody, always have a folding saw with you. This will make it easier to remove large old shoots and avoid splintering the old wood.

The summer lilac is a beautiful shrub that produces beautiful purple flowers. To keep it blooming long and lush, you should prune it regularly, following a few basic rules. All species of butterfly bush tolerate a strong pruning in the spring. However, for some varieties it is not necessary: alternate-leaved summer lilac does not require rejuvenation pruning, but copes with regular thinning.