Plant of the Week
Common Horsetail (Equisetum arvense)
By Robinson Sudan
An herbaceous perennial relative of ferns, common horsetail consists of two types of stems; sterile, non- reproductive and photosynthetic, and reproductive and non- photosynthetic. The latter, 10 to 25 centimeters long with brown scale leaves and a 10 to 40 millimeters long spore cone, emerge in spring then wither and give way to the sterile, photosynthetic stems. These persist from summer until the first frost. It spreads from rhizomes which can grow as deep as six feet.
Equisetum arvense is distributed throughout temperate and arctic areas of the northern hemisphere, growing typically in moist soils. Because of its rhizomatous growth habit and the depth which its roots can reach, common horsetail can be difficult to eliminate from sites where it is unwanted. This has also created concerns about its potential for invasiveness, and indeed it is considered invasive in New Zealand.
This species is not threatened.
Being a relative of ferns, common horsetail does not reproduce via pollen but via spores which are borne on the plant’s reproductive stems.
Equisetum arvense has a long history of cultural use with Native Americans and ancient Roman and Chinese physicians using it to treat a variety of ailments. It is still of interest today as an herbal remedy because of its purported effectiveness as a diuretic. Apart from its use in medicine, the stems were used extensively for their abrasive properties, including being used to remove resin buildup from the wheels used to play the hurdy-gurdy.