A protective mulch made of shredded bark ensures that unwanted weeds are suppressed and do not germinate in the first place. It also protects the soil from erosion and moisture loss. In the following article we will explain to you how to apply the material correctly and which plants benefit from the bark mulch layer.
How does bark mulch work against weeds?
Bark mulch helps against weeds by blocking light, minimizing root support and containing tannins when decomposed. This suppresses the growth of weeds, protects the soil from erosion and moisture loss, and promotes the growth of acid-loving plants.
What is bark mulch?
Bark mulch is small, not yet decomposed pieces of tree bark that are produced as waste during wood processing. The mulching material is available in different grain sizes, open or packed in large bags, from specialist retailers.
However, there is no uniform regulation as to what bark mulch must be like. It is not even legally required that this material be made from pure bark. One hundred percent foreign substances are permitted, as long as they are wood or plant material. Therefore, pay attention to the RAL quality mark, which stands for tested, pure quality.
How does the bark mulch layer work?
Three properties of the mulch material are responsible for the good suppression of weeds:
- Almost all seed-producing weeds are light germinators. No light can penetrate through the dense layer of mulch, so they no longer open.
- The loose structure of the bark mulch offers little support to the roots. Plants growing sparsely through the layer can be easily weeded.
- During decomposition, tannins are released, which have an unfavorable effect on the growth of weeds.
How is bark mulch correctly applied in the bed?
Do not choose a grain size that is too small, as this can hinder the oxygen exchange in the soil. The rule of thumb is: the larger the area to be covered, the larger the pieces of bark mulch should be.
Apply the material here as follows:
- Loosen the soil between the plants.
- Remove all weeds including the roots.
- Apply bark mulch in a seven to ten centimeter thick layer.
- It is recommended to apply nitrogen fertilizer at the same time (€14.00 on Amazon), as the implementation of bark mulch removes nitrogen from the soil.
- Regularly replenish rotted mulch.
Which plants is bark mulch suitable for?
Unfortunately, bark mulch is not a panacea that is equally suitable for all plants. At
- annual plants,
- Bulb flowers,
- Strawberries,
- in the vegetable patch
- in the rock garden
- and in the herb bed
the mulching material should not be used. These plants tolerate acidic pine bark poorly. To suppress weeds, you can use grass clippings or another material as a weed-suppressing top layer.
Acid and humus loving plants like:
- Ferns
- hydrangeas
- Rhododendrons
However, they thrive particularly well thanks to the protective layer of bark mulch. Freshly planted trees and many shade perennials also benefit from a layer of bark mulch.
Tip
In connection with this mulching material, increased cadmium contamination is often mentioned. However, measurements have shown that normal application in the home garden will not have any effects on the soil content of cadmium.
