Vernal pools are seasonal pools, which fill with the snow melt and rains of spring, but which dry over the summer months. By late August, the vernal pool at Armstrong Preserve is awash with Japanese Stiltgrass, an especially invasive grass from Asia. Along with the PRLC Land Steward, Andrew Morgan, and a team of volunteers, we managed to clear the entire pool of stiltgrass. That was 14 very large bags of the stuff!