2019 ASHS Annual Conference

Native flowering forbs and shrubs are primary nectar sources for a large diversity of native insects. These insects have multiple ecological functions, including not only pollination, but also control of many plant herbivore populations through predation and parasitism. Protection and support of native insects for control of agricultural and horticultural pests is one strategy in Conservation Biological Control and is an important integrated pest management technique. Native plantings also provide crucial foraging resources for native pollinator species. The goal of this project is to create demonstration native plant gardens throughout Nevada at both the residential scale and in agricultural settings that will attract native insect pollinators, predators, and parasitoids. The gardens can be used to evaluate the survival and growth of native plant species on an ongoing basis, and to assess their attractiveness to native pollinators and other beneficial insects. Three residential-scale plots were established the fall of 2018 in Reno, Las Vegas, and Overton, Nevada, with 9-month old seedling transplants of fourteen shrub species and two perennial bunchgrasses. A one-third-acre agricultural plot was established in fall of 2018 in Yerington, Nevada, using seeds of 11 forb species and one perennial bunchgrass. Species for both types of sites were selected based on their seed or seedling availability and geographic range, along with a range of pollinator-related characteristics including flower color, flower shape and size, and bloom period. Residential plots were evaluated and plant mortality compensated with replacements in early March 2019. Survival rates of seedlings at the residential plots were between 85% and 90%, and mortality was not concentrated on any particular plant species or family. There were substantial differences in initial plant growth among species in the two southern Nevada locations, with species in bloom or budding in Las Vegas that were still only in rosette or early leaf-out stage in Overton. Plants with the quickest blooms included Baileya radiata, Oenothera caespitosa, and Sphaeralcea ambigua. Residential sites varied in many environmental characteristics, including aspect, elevation, exposure, and soil type, so differences among sites were expected. Future work includes monitoring germination success and early growth at the Yerington location, recording local bloom periods, and monitoring flowers for insect visitation.