Perennial plantings in the city have a variety of functions. They are used as a design element in open space planning and can strengthen the identification, structuring and orientation of an open space. In urban areas, perennial plantings are used aesthetically or functionally in parks, along paths and streets. In spring 2023, a trial area was created in the tree nursery of the Basel municipal nursery in Arlesheim. The aim of this study was to observe the effects of nutrient-loaded biochar on the development of native wild perennials. The aim was to determine the most suitable concentration with which the Basel perennial substrate could be improved. The biochar compost (BKK) was tested in different concentrations (0%, 5%, 10%, 15%). The measurements of the results were carried out from March to May 2023 as part of a master's thesis, which is why the effects are only shown for the short period. Long-term effects can therefore not yet be confirmed. Longer-term studies are needed to ensure that the future Basel perennial substrate also has an improved effect on perennial plantings in the long term and can therefore better withstand the presumed challenges of climate change. As part of the research project, the ZHAW is monitoring the trial area in Arlesheim for at least another three years on behalf of the Basel municipal nursery. Plant physiological and soil chemical and physical properties will be recorded annually. The measurements will be scientifically monitored and documented in a final report. The aim of the project is to develop a Basel perennial substrate that will provide support for the sustainable development of urban and functional perennial areas. The aim is to close the knowledge gaps on the subject of biochar and to better demonstrate its potential, which would also provide insights for use in tree substrates.