| Drought and salinity tolerance were assessed for several Intermountain West native and traditionally used ornamental herbaceous perennials. We irrigated six species established in pots at intervals of 1, 2, and 4 weeks, simulating well watered conditions, moderate drought, and severe drought. Penstemon barbatus showed high tolerance to drought. Lavandula angustifolia and Penstemon x mexicali 'Red Rocks' tolerated moderate drought, but died when exposed to severe drought. Gaillardia aristata and Leucanthemum x superbum 'Alaska' displayed drought avoidance mechanisms in moderate and severe drought. Additionally, we irrigated eight species with water containing CaCl2 and NaCl (2:1 molar ratio) at levels of 0, 1000, 3000, and 5000 mg·L-1 for eight weeks. Mirabilis multiflora, L. x superbum, and L. angustifolia showed high salinity tolerance at levels up to 5000 mg·L-1 but salinity reduced dry shoot and root weights for L. x superbum. Echinacea purpurea exhibited the lowest salinity tolerance of any of the species. |
