Performance of Native Plant Genotypes (Glandularia-Verbenaceae) on Semi-Intensive Green Roofs With Low Maintenance Requirements

Assessing performance and selection of plant species that survive on vegetated green roofs can help to improve green roof functioning under harsh conditions and with low maintenance. It is necessary to increase the available options in the materials for the green roof industry considering long-term plant survival on rooftops of semiarid regions of South America. Although water is often a limiting factor for plants on green roofs, selection of some native materials can succeed in the semiarid regions of Argentina. This research explores the potential of 16 Glandularia genotypes for semi-intensive green roof under low maintenance; they were evaluated by the dynamics of the coverage area, plant survival and health status on modules simulating green roof conditions, during two growing periods (autumn-winter and spring-summer). An overall performance index (green roof fitness index, combining the measurements of plant traits) was applied to compare and rank the materials. Half of the Glandularia hybrids in process of genetic improvement can be considered as promising materials. The good performance of most plant indicators (e.g., dynamics of coverage area, health status, survival ) in these recommended materials allow us to predict their adequate performance on semi-extensive green roofs under semi-arid conditions