Invasive species like tree-of-heaven, Japanese stiltgrass, autumn olive, and oriental bittersweet create serious problems in ecosystems. Plant invaders contribute to the decline of native flora and fauna; decrease soil, water, and air quality; and have detrimental economic impacts and adverse effects on human health. Soil scientist and Master Gardener Linda Blum will describe why some plants become invasive and the factors that contribute to their spread. Registration for this free program will be available here beginning September 16.