Nature-based solutions are promising for climate adaptation and environmental management in urban areas, but urban conditions are stressful for vegetation. In particular, the interaction of drought and high temperatures may be detrimental. Guiding plant selection for urban greening with native species requires a far better knowledge of plant adaptations and stress acclimation. We tested the physiological responses of four candidate calcareous grassland species for green roofs and walls to the combined effects of drought and high temperatures under controlled conditions. The tested species proved relatively resistant to stress despite different strategies to protect the photosynthetic apparatus, maintain water balance, and repair damages. Based on the physiological responses, we rank the species in descending order of resistance to the stress factors tested: Trifolium medium > Festuca ovina > Carex flacca > Potentilla reptans, but all four can serve as potential candidates for green walls and roofs. Physiological stress screening of plant species for use on green roofs and walls supplements the habitat template approach to provide a stronger and wider base for prioritizations.

Climate change and man-made pollution can have a negative impact on the establishment of Miscanthus plants in the field. This is particularly important because biomass can be produced on marginal land without conflicting with food crops. The establishment success depends on the hybrid chosen, the cultivation method, the climatic conditions, and the concentration of pollutants in the soil. There are several ways to increase the survival rate of the plants during the first growing season and after the first winter. One of them is the application of biochar and photodegradable plastic mulch, which can provide a solution for soils polluted with trace elements (TMEs). The aim of this study was to investigate the application of plastic mulch and biochar separately and in combination at the planting stage for two Miscanthus hybrids planted by the rhizome method (TV1) and seedling plugs (GNT43) on soils contaminated with trace metal elements (Pb, Cd, Zn). TV1 seems unsuitable for TME-contaminated field cultivation, as the survival rate was <60% in most treatments studied. The selected treatments did not increase the survival rate. Furthermore, the application of plastic mulch in combination with biochar resulted in a significant reduction of this parameter, regardless of the hybrid studied. The applied agrotechnology did not influence the TME accumulation in the aboveground plant parts in TV1, while Pb and Cd in GNT43 showed significantly higher values in all treatments. Contrary to expectations, biochar and plastic mulch applied separately and together neither increased survival nor reduced the accumulation of toxic TMEs during establishment on soil contaminated with TMEs and after the first growing season.