Pruning forsythia: when & how?

Forsythia shines a bright yellow on the first warmer days. But the wrong cut can destroy the entire flower. Our best tips for pruning forsythia.

Forsythia (Forsythia × intermedia) is one of the most popular shrubs in gardens and is known to most by its striking yellow flowers. The plant, which belongs to the olive family (Oleaceae), can delight every year with the right technique. But if the forsythia is cut at the wrong time, the consequence will be no flowers the next spring. We show how to avoid mistakes when pruning.

Pruning forsythia: when is the right time?

The right time is always crucial for a lush flowering of the forsythia. The yellow–flowered plant is what’s known as mesotonic in botany, which means that new shoots grow almost exclusively from the main shoot. Only the fresh shoots produce the bright yellow flowers every year. Find out below when you should and should not cut the flower.

Pruning forsythia in autumn?

A common mistake in the care of forsythia is pruning in the autumn. Most of the new shoots that grow in the summer and bear the flower the next spring are removed. The ambitious gardener finds out the hard way the next spring, when the magnificent flowers fail to appear. The following therefore always applies: never cut off new shoots in autumn, but old and dead branches can be removed without hesitation.

Trimming forsythia after flowering

Even though forsythia should not be pruned in the autumn, it is still advisable to prune the new shoots once a year. The best time for this is the period from spring to early summer after the flowering of forsythia. During the summer, this still gives the plant enough opportunity to form fresh shoots for the next year’s renewed flowering.

To identify the right time when pruning forsythia, pay attention to the following tips:

• Never cut new shoots in autumn
• In autumn remove only old, dead branches
• Cut the shoots after flowering

Pruning forsythia: instructions

Pruning forsythia is generally useful to keep the plant healthy in the long run and to guarantee the desired flowering in spring. Below we present different types of cuts.

Cutting back forsythia regularly

The thinning pruning mentioned earlier involves carefully cutting off flowered and old shoots to allow enough light to reach the heavily branched interior of the shrub. This will also preserve flowering for the next year. It is best to perform this pruning every year after flowering, this will greatly increase the formation of flowers. In addition, it is useful if overhanging, as well as diseased and old branches are removed throughout the year.

Radically pruning forsythia: bringing neglected forsythia into shape

To trim a sprawling forsythia back to size, so-called maintenance pruning is suitableideal. In the process, at least every three years, cut back the bush relatively hard and remove strong branching. An even more radical, but quite useful method is rejuvenation pruning. This should be done when the forsythia is affected by a fungus or is growing sparsely. To do this, cut down the bulk of the shoots relatively strongly, leaving only a few branches.

If you follow these tips, nothing will stand in the way of the forsythia’s health and a lush bloom.

For more information on forsythia, for example, planting or propagation, see this review article.