In the warm-temperate regions of Uruguay and Argentina, the adoption of warm-season perennial grasses has been very limited. Slow and unpredictable establishment has been perceived as one of the most limiting factors for their use either as pure stands or in mixtures with cool season grasses. Among the best studied species are P. dilatatum and related species and P. notatum. In this study we analyzed a network of locations and sowing dates to understand the responses of single clone or inbred line of P. dilatatum cv. Chirú (Chirú), P. dilatatum ssp. flavescens (Flav), P. urvillei (Urv) and P. notatum (Not) to environmental factors and determine appropriate sowing dates.