ATHENS, GREECE--Green roofs are being studied as a means to increase vegetation and preserve aesthetics in old Mediterranean cities. In order to preserve ancient cities' local character and biodiversity, researchers are looking to native plant species that can withstand the low water environments that are necessary in lightweight green roof design. Xerophytes--species of plants that have adapted to survive in environments with little water--fit well in green roof construction plans, creating lightweight roofs that don't compromise ancient buildings' structural concerns. A research team in Athens explored the use of three Mediterranean aromatic xerophytes, Artemisia absinthium, Helichrysumitalicum, and H. orientale, for use in an extensive green roof design. The study, published in HortScience, also investigated the practice of using of locally produced grape marc compost to promote drought resistance, and looked at the effects of different planting depths and irrigation frequencies on the three aromatics.
According to the Maria Papafotiou from the Department of Crop Science at the Agricultural University of Athens, most Mediterranean cities are centered around their old nucleus, which in many cases is characterized as a historical heritage. "These cities lack areas that could be converted into conventional green spaces, and thus there is an increasing interest in green roof systems. Green roofs are still relatively uncommon in Mediterranean countries, although these areas would significantly benefit from the ecological and technical functions of this technology," Papafotiou explained.
The scientists planted rooted cuttings of the three aromatics in a green roof infrastructure they then placed on a fully exposed flat roof in Athens. Two types of substrates were used (grape marc compost:soil:perlite and peat:soil:perlite ) at two substrate depths, 7.5 cm (shallow) and 15 cm (deep). The team
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American Society for Horticultural Science