Screening for drought tolerance of ground cover species for urban green spaces

Abstract

Urban green spaces provide recreation, aesthetic, and ecological benefits, but many local authorities face funding and water scarcity challenges. Drought-tolerant ground cover species offers a sustainable solution for improving water use efficiency. Hence, this study investigated the water stress tolerance capacity of three ground cover species Zebrina pendula, Pellionia repens, and Hemigraphis alternata, under four species-specific irrigation intervals as treatments. For each species, 20 plants were assigned to each treatment and Z. pendula was irrigated daily (control), every 6, 12, and 18 days; P. repens daily (control), every 4, 8, and 12 days; and H. alternata daily (control), every 2, 3, and 4 days. The experiment was arranged in a completely randomised design and general linear model followed by Tukey’s pair-wise comparison was used to analyse data. Survival and growth parameters were recorded. Growth parameters differed significantly among the species-specific treatments (p < 0.05). Zebrina pendula recorded 100% and 95% survival in once every 6-day and 12-day interval irrigation schedules, and thereafter, it was reduced to 65% in an 18-day irrigation interval. Pellionia repens recorded 100% survival throughout, while in H. alternata, 100% survival was recorded once in every two-day irrigation schedule, and thereafter, it was reduced to 40% and 20% respectively. Irrigation every two days showed high mean growth parameters in H. alternata, every eight days in P. repens and every 12 days in Z. pendula. Hence, P. repens and Z. pendula have strong adaptive traits under water stress conditions, whereas P. repens is the most resilient, whereas H. alternata is not recommended for drought-tolerant designs in sustainable green spaces.