Designing greener cities with water use efficient medicinal and aromatic plants

In the Mediterranean urban environment, plants have to face several abiotic conditions (e.g., air pollution, water scarcity, soil contamination) that can represent sources of stress, compromising their growth and aesthetic qualities. Medicinal and aromatic plants (MAPs) have generally limited water and nutritional needs and high tolerance to contaminants, such as heavy metals. These low maintenance requirements, together with a high aesthetic value, make MAPs more and more used in urban green areas. Salvia spp. and Helichrysum spp. with abundant and long lasting blooms and grey foliage, are widely employed as ground cover, traffic divider, borders, road slopes and roundabouts and for vertical gardens. In terms of increasing biodiversity more generally, MAPs can also represent a sink of abundant nectar for pollinating insects even in the urban environment. In the present study, we analysed some of the most important MAPs used in urban green areas, highlighting their water needs.