Rough Horsetail
Equisetum hyemale
Family: Equisetaceae
This is a riparian, spreading, reed-like perennial to 3 ft tall (sometimes taller), suckering out almost indefinitely if water is available. The tiny leaves are joined together around the stem, forming a narrow black-green band or sheath at each joint. Like other Pteridophytes (ferns and their relatives), scouring rush does not produce flowers or seeds—they reproduce by spores like ferns do.
This plant can grow in full sun to full shade, and is best with regular water. Though it can grow in swampy, submerged situations, it doesn’t require such and can actually tolerate some dry spells, especially in cooler weather. Hardy to -35°F.
In a pond situation this plant makes great habitat for water insects and larvae for insects like dragonflies. As long as the water is highly oxygenated and flowing, it won’t encourage mosquitoes. Rough horsetail is a major component of habitat that is extremely important to a number of organisms, especially birds that nest in the horsetail fields.
Equisetum is a "living fossil", the only living genus of the entire subclass Equisetidae, which for over 100 million years was much more diverse and dominated the understorey of late Paleozoic forests. Some equisetids were large trees reaching to 100’ tall.
the stems are coated with abrasive silicates, making them useful for scouring (cleaning) metal items such as cooking pots or drinking mugs, particularly those made of tin. Equisetum hyemale, rough horsetail, is still boiled and then dried in Japan to be used for the final polishing process on woodcraft to produce a smooth finish. The stems are used to shape the reeds of reed instruments such as clarinets or saxophones. This species is also used as a horse medicine, taken for kidney problems, constipation. The leaves were burned as a disinfectant. Plants used as an insecticide for washing hair, taken for irregular menstruation, for bladder or prostate pains, as a diuretic, as an eye wash, taken for diarrhea, gonorrhea, to help clear the system after childbirth, to speed up delivery, for sores. Also eaten as a food, used as fodder, for tools and basketry, mat weaving, and used as a ceremonial medicine.
Equisetum is from equus, horse and seta, bristle, while hyemale means of the winter, or flowering in winter. There are 41 species around the world. There are 3 species and one natural hybrid found in Arizona.
Found in moist soil along streams and creeks, and in marshy meadows from 2,500-8,500 ft. throughout the Holarctic Kingdom, found in North America, Europe, and northern Asia.
A similar species, Smooth Horsetail (Equisetum laevigatum) is found in damp seeps, along streams, and at the bottom of canyons, from 3,000-8,000 ft. Photo by Ethan Bidwell, iNaturalist
Field Horsetail (Equisetum arvense) is found in wet soil of meadows and on stream banks from 4,500-9,000 ft. Photo by Max Licher, SEINET
Hybrid between E. hyemale and E. laevigatum, distinguished by looking at the sterile strobili, which when broken open will reveal a cottony mass of elaters, but not mature green, globose spores. Photo by Sue Carnahan, SEINET