Flowering perennials and ornamental grasses do not do well when your soil is covered in tree bark.
Bark digests, causing the soil to acidify. Most flowering perennials and ornamental grasses do not tolerate this but prefer a neutral to lime-rich soil. Moreover, it forms a cold, humid layer and creates the ideal climate for fungi.
Bark can be used for trees, shrubs and hedges.
Anti-root fabric is also not recommended because the plants do not have the space to grow. The quality of the soil underneath the fabric will decline. The plants suffocate and you will never get a fully covered garden.
If you want to cover the soil, you can then use an inert material such as gravel or lava. These do not digest and are therefore perfect to permanently cover the plant border. They prevent compaction of the soil when trod on, facilitate maintenance (fewer weeds = less weeding) and form an insulating layer in the winter period.
In the case of a new planting, it is best to first place the inert gravel evenly and everywhere at the same thickness (7 cm). The plants can then be planted with a prairie planter designed by Bart Spruyt.
However, covering the soil is not necessary. Keep in mind that you use the maximum planting density when you want to limit maintenance (weeding, etc.).
You can find the right planting density per species in the online catalogue.