S07 - Session P1 - Selection of ornamental species with different respiratory metabolism for use on green roofs

Authors: Carlyn Omoze Yakubu, Stella Aurea C. Gomes da Silva, Vivian Loges *, Simone Santos Lira Silva, Francesco Orsini, Giorgio P. Gianquinto, Alessandra Bonoli

It is desirable that green roof present multi-functionality through harmonized environmental services and ornamental potential. This research aims to characterize and select ornamental species with different respiratory metabolism and different substrates depth for use in green roofs. The experiment was conducted in a roof the Engineering Campus of the University of Bologna (UNIBO), Italy. The species cultivated in beds with 8, 10 and 12 cm in depth, were: metabolism C3 - Begonia cucullata Willd. and Salvia nemorosa 'Bordeau Steel Blue' (Sage); metabolism CAM - Crassula capitella cv. Campfire; Echeveria pulvinata cv. Frosty; Sedum album L., Sedum palmeri S. Watson; Delosperma cooperi (Hook. F.) L. Bolus; D. cooperi cv. Orange Wonder; metabolism C4 and CAM - Portulaca grandiflora Hook. The survival rate, general appearance, flower production, type of growth and height were evaluated. The D. cooperi and D. cooper cv. Orange Wonder (CAM) stood out with the highest flower production, ranging from moderate to intense production, with a pleasant appearance, mainly in substrate with 12 cm depth. The P. grandiflora (C4 and CAM), featuring elevate survival rate (92%), presents moderate flower production and pleasant appearance, with plant's height ranging 15 to 20 cm. B. cucullata and S. nemorosa (C3) (survival rate of 83%, and erect growth of 20 to 25cm) demonstrated pleasant to very pleasant appearance and moderate flower production. C. capitella cv. Campfire, E. pulvinata cv. Frosty, S. album , S. palmeri (CAM), although featuring survival rate of 83%, featured deficient appearance, and no flower set. The D. cooperi , D. cooperi cv. Orange Wonder (CAM), P. grandiflora (C4 and CAM), B. cucullata and S. nemorosa (C3) are indicated for uses in multifunctional green roof, preferably in substrates with 12 cm depth, for resisting wide temperatures ranges (9 to 43°C) while preserving their ornamental characteristics.