The aim of this study was to estimate the water demand for purple coneflower (Echinacea purpurea L.) on a green roof in Bydgoszcz urban aglomeration, depending on projected climate change. A scenario of climate changes for Poland SRES: A1B was taken into account. Water needs of purple coneflower were determined by the method of plant coefficients. Based on adopted assumptions and performed calculations, it was found that in the forecast period (2021-2050) there will be greater variability in the water needs of the Purple coneflower. In the forecast period, a clear tendency towards increasing water needs of the purple coneflower is expected ( every 8.9 mm in a decade). Total rainfall deficiencies for the entire growing season of the purple coneflower (11. May - 10. July) - in an average, moderately dry and very dry year - are expected to decrease to a minor extent, from 205,9 mm, 259,4 mm and 301,9 mm in the comparative period to 198,6 mm, 254,6 mm and 298,5 mm in the forecast period, respectively (which results from more rainfall in June and July in the scenario of climate changes, which was used.) ...
