Early colonizing plant species grow on high, recently-graded concrete and stoney debris near the vertical pipe. These include New England Aster, Pearl-Millet, Evening Primrose, Heath Aster, Yellow Bush Clover, White Moth Mullein, Annual Ragweed, and Early Goldenrod. These plants demonstrate that the presence of some hardy perennial species does not necessarily mean the environment has been static for multiple seasons. 25 October 2022.