March 10, 2025 Peter van Dijk

Pruning St. John's Wort (Hypericum)

St. John's Wort, also known as Hypericum, is a versatile garden plant that you can use both as a ground cover and as a low hedge plant. With its bright yellow flowers and graceful berries, it is a real eye-catcher in the garden. To keep the plant healthy and in full bloom, regular pruning is important. In this blog, you can read everything about pruning and caring for St. John's Wort.

When to Prune St. John's Wort?

Pruning St. John's Wort (Hypericum) is an important maintenance task to keep the plant healthy, compact, and full of flowers. By pruning at the right time, you promote growth and prevent the shrub from becoming too overgrown. The most important pruning times are spring and autumn.

St. John's Wort Pruning Spring (March-April)

This is the ideal time for rejuvenation pruning. Prune the plant back heavily to about 10-15 cm above the ground. This stimulates healthy, compact growth and ensures that the shrub blooms profusely in the summer. St. John's Wort blooms on new wood, so rigorous pruning in the spring helps to improve flowering and keep the shrub in shape.

Pruning St. John's Wort Autumn (September-October)

After flowering in the summer, you can perform light maintenance pruning in the autumn. Remove spent flowers and branches to make the plant look neat and tidy. This prevents the shrub from becoming overgrown and helps prevent diseases and pests.

Do you want to keep the plant looking beautiful all year round? Then you can also prune away dead or damaged branches in between. This way, the St. John's Wort remains vital and graceful in the garden!

How to Prune St. John's Wort?

Pruning St. John's Wort (Hypericum) is essential to keep the plant healthy, give it a beautiful shape, and promote abundant flowering. By pruning correctly, you stimulate growth and prevent the plant from becoming overgrown. Here is how you can do this effectively:

Steps to Prune Hypericum

1. Use the right tools

For accurate and neat pruning, it is important to use sharp tools, such as pruning shears or hedge trimmers. Blunt shears can damage the branches, which increases the risk of disease. Make sure your tools are clean so that you do not spread diseases between plants.

2. Remove dead and damaged branches

Always start by removing dead, damaged, or diseased branches. You can usually recognize these branches because they are brown or black, or they are broken or dried out. Cut these branches off as close to the base of the plant as possible. Use sharp scissors to make a clean cut. This prevents diseases from spreading and ensures that the plant can focus its energy on healthy growth. When pruning dead branches, it is important not only to remove the visible dead branches, but also branches that are starting to rot under the bark or show signs of disease. If you touch damaged branches, it is good to disinfect your tools to prevent diseases from spreading between the plant parts. 3. Removing spent flowers Removing spent flowers is important to keep the plant looking neat and to encourage further flowering. Cut off the flowers just above the leaf node so that the plant can focus its energy on developing new flowers instead of seed production. When removing the flowers, it is important not to cut away too much of the branches, as this can otherwise hinder flowering. Always try to make a neat, clean cut so that no damage is caused to the plant.

4. Finishing

After pruning, you can finish the plant by gently loosening the soil around the base with a small cultivator or hand fork. This improves root aeration and ensures better water absorption. If you wish, you can also add some compost or organic fertilizer to nourish the plant and support healthy growth. This promotes the growth of new shoots and ensures that the plant emerges stronger from the pruning. Don't forget to clean your tools thoroughly after use to prevent diseases.

Pruning Hypericum Species

There are different species Hypericum, and not every species requires the same pruning method. Below, we discuss the most popular varieties.

Pruning Hypericum Hidcote

Hypericum 'Hidcote' is one of the most popular varieties with large, bright yellow flowers. Prune this plant back heavily in March to about 15-30 cm above the ground. This stimulates bushy growth and abundant flowering. In the autumn, you can apply light shaping pruning. Regularly remove any dead or wilted branches to keep the plant healthy.

Pruning Hypericum Inodorum

The Hypericum Indorum is primarily grown for its decorative berries. Prune it back lightly in March to stimulate new growth and abundant berry formation. Avoid drastic pruning, as this can reduce flowering. Remove spent flowers after flowering to keep the plant tidy and prevent further seed formation.

Pruning Hypericum Calycinum

Hypericum Calycinum, also known as St. John's Wort, is a vigorous ground cover. It can grow up to 50 cm tall. Prune it back in early spring to about 10 cm above the ground to promote dense and fresh growth. Regular pruning promotes the healthy spread of the plant, ensuring it effectively retains its ground-covering function.

St. John's Wort Care after Pruning

After pruning, it is important to take good care of the plant. Here are some tips:

Fertilizing: Apply organic fertilizer in the spring to stimulate growth.
Watering: Especially after deep pruning, the plant needs sufficient water.
Mulching: A layer of mulch around the base of the plant helps retain moisture and prevents weeds.
Check for diseases: After pruning, the plant is more susceptible to fungi and pests. Check the leaves regularly.