S07 - Session P1 - Herbaceous ornamental species for extensive green roofs

Authors: Mariana Grassi Noya, Francine Lorena Cuquel *

Green roofs frequently mitigate several urbanization consequences. They help to mitigate storm-water runoff from building surfaces by collecting and retaining precipitation, thereby reducing the volume of flow into storm-water infrastructure and urban waterways; they improve the air quality; they increase the energy use efficiency; they favor the habitat for wildlife biodiversity; they decrease the urban heat-island effects, and in addition, they contribute to the landscape value. A good green roof planning must carefully choose the best vegetation for each environment, considering the local weather, and substrates' depth. In the South of Brazil, there are few herbaceous ornamental species indicated for extensive green roofs. This research was performed in Curitiba City, the State Capital, a "Cfb" subtype Köppen Climate Classification (Marine West Coast Climate), with few extremes of temperature, and ample precipitation in all months, between 35N and 60S latitude, with 62.2°F average yearly temperature. Eight locally adapted species were chosen for this research Aptenia cordifolia, Echeveria elegans, Gazania rigens, Lysimachia congestiflora, Ophiopogon japonicus, Osteospermum ecklonis, Oxalis vulcanicola and Zephirantes candida . This research was carried out in an extensive green roof prototype, simulating a conventional roof, with 5% slope. Vegetation covering rate, regrowth, and establishment time were observed during 12 months, every two weeks. Echeveria elegans and Ophiopogon japonicus were the best species, and the extensive green roof remained with a wide green covering.