2019 ASHS Annual Conference

Sego Supreme^TM is a designated plant introduction program at USU Botanical Center and USU Center for Water Efficient Landscaping. This plant selection program is to introduce native and adaptable plants into the arid west landscapes for aesthetic landscape and water conservation. The plants are evaluated for disease resistance, drought tolerance, and invasiveness. However, salt tolerance is not one of the factors considered during the evaluation process. Salt tolerance of four Sego Supreme^TM plants (Aquilegia barnebyi, Clematis fruticosa, Epilobium septentrionale, and Tetraneuris acaulis var. arizonica) was evaluated in a greenhouse experiment. Uniform plants were irrigated weekly with a nutrient solution at an electrical conductivity (EC) of 1.25 dS·m^-1 as control or a salt solution at an EC of 2.5 dS·m^-1 (EC 2.5), 5.0 dS·m^-1 (EC 5), 7.5 dS·m^-1 (EC 7.5), or 10 dS·m^-1 (EC 10) for 8 weeks. At harvest (8 weeks after irrigation initiated), A. barnebyi in EC 5 had slight foliar salt damage with an average visual score of 3.7 (0 = dead; 5 = excellent), however, in EC 7.5 and EC 10, more than 50% of the plants were dead. However, C. fruticosa, E. septentrionale. and T. acaulis had minimal or no foliar salt damage with averaged visual scores of 4.2, 4.1, and 4.3 in EC 10, respectively. As the salinity levels of irrigation water increased, plant height, leaf area, and shoot dry weight of C. fruticosa and T. acaulis decreased linearly; plant height of A. barnebyi and E. septentrionale also declined linearly, but their leaf area and shoot dry weight decreased quadratically. Compared to the control, the shoot dry weight of A. barnebyi, C. fruticosa, E. septentrionale, and T. acaulis in EC 10 decreased by 71%, 56%, 70%, and 48%, respectively. A. barnebyi and C. fruticosa did not bloom during the entire experiment. Elevated salinity reduced the number of flowers in E. septentrionale and T. acaulis. In summary, C. fruticosa and T. acaulis were more tolerant to salinity, followed by E. septentrionale, and A. barnebyi had the least salt tolerance.