2019 ASHS Annual Conference

Ornamental grasses are commonly used in urban landscapes in the Intermountain West area of the western United States including Utah. Eragrostis spectabilis (purple love grass), Miscanthus sinensis 'Gracillimus' (maiden grass), Panicum virgatum 'Northwind' (switchgrass), and Schizachyrium scoparium (little bluestem) were evaluated in a greenhouse. Plants were watered with a fertilizer solution at an electrical conductivity (EC) of 1.2 dS∙m^-1 (control) or salt solutions at an EC of 5.0 or 10.0 dS∙m^-1 roughly every four days. At harvest (65 days after treatments initiated), E. spectabilis and M. sinensis had minimal foliar salt damage when irrigated with a salt solution at an EC of 5.0 dS·m^–1, while P. virgatum and S. scoparium exhibited no foliar salt damage. At an EC of 10.0 dS·m^–1, E. spectabilis and M. sinensis displayed slight foliar salt damage with visual scores greater than 3 (0 = dead; 5 = excellent), but P. virgatum and S. scoparium still had no foliar salt damage. Compared with the control, salt solutions at an EC of 5.0 and 10.0 dS·m^–1 reduced the shoot dry weight of all ornamental grasses by 25% and 46%, respectively. The leaf sodium concentration of E. spectabilis, M. sinensis, P. virgatum, and S. scoparium irrigated with a salt solution at an EC of 10.0 dS·m^–1 increased by 14.3, 52.6, 5.3, and 1.7 times, respectively, and the chloride concentration increased by 9.4, 11.1, 2.8, and 2.7 times, respectively. All tested ornamental grasses had a very strong salt tolerance. P. virgatum and S. scoparium could restrict sodium and chloride accumulation in the leaves and were relatively more tolerant to salinity than E. spectabilis and M. sinensis.