Equisetum hyemale #1 (Horsetail / Scouring Rush)

Horsetail is also known as Scouring Rush because of its usefulness as a scouring tool, due to the high silica content in the ridged stems. It is not a type of rush, however. It is an ancient plant that reproduces by spores, spreads far and wide by thick, ropey rhizomes, and remains truly evergreen. In cold winters, the top few inches of the unbranched stems may die back but winter interest remains high. The look of the stems and growth habit resemble bamboo, and like bamboo, this plant can spread very aggressively if planted in favorable conditions. It thrives in any wet soils and forms dense, strongly vertical colonies which provide great cover for wildlife. Once established, these colonies can be nearly impossible to eradicate, so use caution in choosing a planting site and perhaps consider planting in a sunken pot or using a soil barrier.

Sources:
Native Ferns, Moss, & Grasses by William Cullina
Eastern/Central Medicinal Plants and Herbs by Steven Foster and James A. Duke
Missouri Botanical Garden
Lady Bird Johnson Wildflower Center
Illinois Wildflowers
Grow Native! Salt-Tolerant Native Plants

Photo Credit:
Mature Patch: Elie Ardy, CC BY-SA 4.0, via Wikimedia Commons
Stem Cross Section: Stefan.lefnaer, CC BY-SA 4.0, via Wikimedia Commons