Propagation of atlantic climate native species of the Genus Sedum for use in extensive green roofs

Abstract

In this study, we evaluated the rooting potential of herbaceous cuttings of Atlantic climate native species of Sedum which can be interesting for use in extensive green roofs. The species are native of Galicia and León (NW Spain), which have an Atlantic climate. The following native species were considered: S. album, S. alpestre, S. anglicum, S. brevifolium, S. hirsutum and S. acre. A commercially available species, S. rupestre (S. reflexum), was used as a control for comparison with the native species. The trial was established in June 2011 in a greenhouse equipped with a fog-system and bottom heat. The cuttings used in the trials were harvested from mother plants established from wild populations collected in coastal and inland areas of Galicia and grown in a growth chamber. The cuttings were inserted directly (i.e. without prior hormonal treatment) into individual cells. The rooting media consisted of a mixture of Sphagnum peat moss, pine bark compost and vermiculite (1:1.5:2.5, v/v/v). A split plot design with 5 replicates per species-origin and evaluating date and 7 cuttings per replicate was used. Rooting percentage, visual rooting score and number of primary roots were determined 15 and 30 days after cutting. The quality of roots was evaluated as total root length and number of root tips, with a Delta-T Scan system. The length and dry weight of the shoots were determined 90 days after cutting. The mean rooting percentage was 87% on the first evaluating date and 95% on the second. The rooting percentage differed significantly between species, with the lowest values obtained for S. hirsutum of coastal origin (68%) 15 days after cutting. For the other species, the rooting percentages were similar, varying between 94 and 100% at 30 days after cutting. Root development also differed significantly between species and origins. In general, S. anglicum (from inland locations), S. album (from inland locations) and the control species (S. rupestre) developed larger root systems within the shortest space of time. The findings showed the propagation performance of Atlantic climate native species of Sedum was good. The plants can be propagated on a commercial scale from cuttings within a short time, varying between 1 and 2 or 3 months depending on the species