Effect of Low Water and Nutrient Environments on Growth Characteristics of Eight Native Ornamental Perennial Species

Native plants are often recommended to reduce inputs in urban landscapes. Morphological and physiological responses of Liatris spicata, Liatris pycnostachya, Liatris aspera, Liatris scariosa, Liatris cylindracea, Amsonia tabernaemontana, Thermopsis caroliniana, and Baptisia australis to varying fertility and moisture conditions were studied to determine their ability to reduced input. A field study showed wet adapted species L. pycnostachya and L. spicata had greater increased dry mass in response to irrigation compared to dry adapted species while there was no response to fertilizer in all species. A greenhouse trial showed T. caroliniana and B. australis had greater decreased dry weight compared to other species. A. tabernaemontana, L. scariosa, and L. cylindracea displayed decreased growth and photosynthesis with high water treatment. For all other species, higher water availability increased photosynthetic rate and growth. A third study showed no significant response in root morphology to deficit irrigation. This research shows the ability of native plants to reduce inputs in species dependent. Ontario Ministry of Agriculture, Food, and Rural Affairs