Equisetum arvense

Equisetum arvense, the field horsetail or common horsetail, is an herbaceous perennial plant in the Equisetidae (horsetails) sub-class, native throughout the arctic and temperate regions of the Northern Hemisphere. It has separate sterile non-reproductive and fertile spore-bearing stems growing from a perennial underground rhizomatous stem system. The fertile stems are produced in early spring and are non-photosynthetic, while the green sterile stems start to grow after the fertile stems have wilted and persist through the summer until the first autumn frosts. It is sometimes confused with mare's tail, Hippuris vulgaris.

Rhizomes can pierce through the soil up to 6 feet (1.8 m) in depth. This allows this species to tolerate many conditions and is hard to get rid of even with the help of herbicides.