Extensive green roofs (EGR) spaces constitute harsh and stressful growing environments, and consequently a limited range of plants species that can be routinely used there. The habitat template hypothesis suggests that EGR can be analogous as natural environments, what makes native plants as an alternative for these conditions. This paper aimed to assess the potential use of 15 native plants from Córdoba Province (Argentina) for green roofs, based on cover ability, survived rates and health status observations during a period of 414 days. Sedum acre L. was used as the control. Glandularia x hybrid, Phyla nodiflora (L.) Greene, Melica macra Nees, Eustachys retusa (Lag.) Kunth and Grindelia cabrerae Ariza kept up a 60% of coverage during all the period of study. The first two species had an outperformed green coverage (at 72th day; 95% and 98% respectively) in relation to the control species (Sedum acre; 87%). Eustachys retusa and Grindelia cabrerae grew progressively and kept their coverage constant proximally to 65%. Sedum acre, Grindelia cabrerae, Hysterionica jasionoides Willd, Melica macra, Phyla nodiflora, stood out in plant survival rates; but S. acre suffered changes in health status throughout the evaluation period, especially with low temperatures or at high humidity conditions. It is necessary to underline the reseeding potential of Eustachys retusa, a process that could guarantee perpetuation of the species on EGR.

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As part of the breeding program of Glandularia (Verbenaceae), here we performed interspecific crosses to select the most outstanding materials and define trait associations for descriptors related to ornamental performance. The experimental material consisted of populations of three species of Glandularia and their offspring. Crosses were obtained by artificial hybridization using the diallel method. Reproductive efficiency values ranged from 10.4% to 60.7%. Ornamental characterization on pot and bedding plants were obtained from hybrids and their parents, after analysation through a principal components analysis. The pot plant fitness index values for parents and offspring ranged between 0.56-0.76 and 0.56-0.78, respectively; the bedding index values for parents and offspring ranged between 0.17-0.99 and 0.15-0.99, respectively. The features selected for the construction of the indices were effective for discriminating the ornamental aptitude of the different plant materials. Glandularia hybrids showed a remarkable ornamental performance for different purposes, some hybrids performing better as pot plants, others for bedding plants, and some for both. Keywords ornamental characterization, Glandularia spp., hybridization, indices, performance, reproductive efficiency populations of different species with the potential to develop traits of commercial interest and efficiency for the breeding program (Santos et al., 2011). In central Argentina, there are native populations of Glandularia glandulifera (Moldenke) Ragonese, G. peruviana L. Small and G. platensis (Spreng) Schnack and Covas. These species provide an interesting floriculture option to be used in semi-arid climatic conditions