Equisetum arvense

Field Horsetail

Field Horsetail, Frijoles Creek Canyon, New Mexico, Photo © 2002 by Earl J.S. Rook
Field Horsetail
Frijoles Creek Canyon, New Mexico
Photo © 2002 by Earl J.S. Rook

Flora, fauna, earth, and sky...
The natural history of the northwoods


  • Equisetum, from the Latin, equus, "horse", and seta, "bristle, animal hair"
  • arvense, from the Latin, arvum, "field, cultivated land, plowed land"
  • Field Horsetail, from its common habitat, a direct translation from the botanical Latin.
  • Other common names include: Common Horsetail, Horsetail, Bottlebrush, Foxtail, Horse Pipes, Pipe Weed, Jointed Rush, Cat's Tail, Mare's Tail, Pinetop, Pine Grass, Snake Grass, Shave Grass, Paddy's Pipe, Corn Horsetail, Toadpipe (UK), Prêle des Champs, Petite Prêle, Queue de Cheval, Queue de Rat, Queue de Renard (Fr), Åkersnelle (Nor), Åkerfräken, Rävrumpa, Krypfräken (Swe), Ager-Padderokke (Dan), Peltokorte (Fin), Klóelfting (Is), Acker-Schachtelhalm (Ger), Heermoes, Akkerpaardestaart, Kattestaart, Librus, Moeraspaardestaart (Dut), Rabo de Cavalo, Cauda de Cavalo, Erva Carnuda, Equisseto (Bra), Tsukushi (Jpn), Earball an Eich (Gaelic), Põldosi, Lambanisa, Lehmanisa, Seatilk, Tilkhain, Konnakuusk, Põldkuus, Oravasaba (Estonia)


  • Kingdom Plantae, the Plants
    • Division Equisetophyta, the Horsetails
      • Class Equisetopsida, the Horsetails
        • Order Equisetales, the Horsetails
          • Family Equisetaceae, the Horsetails
            • Genus Equisetum, the Horsetails
  • Taxonomic Serial Number: 17152
  • Also known as Equisetum calderi
  • Hybridizes with Water Horsetail (Equisetum fluviatale).


  • A bushy native, perennial, rhizomatous horsetail. Highly variable.
  • Sterile stems jointed (joints about 1" long and 1/24" - 1/16" in diameter), hollow, six to nineteen grooved, usually erect, bearing up to 20 whorls of slender branches, 2"-24" tall and terminating in a long, naked point. Leaves scalelike, deciduous, inconspicuous, in whorls at the nodes; are connected at their bases.
  • Fertile stems short, succulent, yellowish, ephemeral shoots with only two to five joints, generally 2"-12" tall, that appear early in the growing season. The green, sterile shoots develop later, by which time the fertile shoots usually have wilted. Unique among our Horsetails, this fertile stem never turns green.
  • Epidermis of both types of stems has regularly arranged, silicified projections.
  • Branches ascending, rarely rebranching; bushy, solid, regularly whorled.
  • Cones long stemmed, blunt tipped, 0.4"-1.4" long, on tip of fertile stem.
  • Rhizomes branched and creeping; similar to the aerial stems except that they are not hollow. Storage tubers are produced on the rhizomes. Rhizomes extend to a depth of 40" or more; 50% by weight in the top 10" of soil, 23% in the next 9", and the rest deeper. Successive, layered horizontal rhizome systems occur at about 12" intervals and have been found at depths exceeding 6' and extending yet deeper.
  • Root development takes place at the bases of lateral branch buds, both on rhizomes and erect shoots.


  • Identifiable as Horsetail by the upright, hollow, jointed, cylindrical stems with inconsequential and easily overlooked leaves.
  • Distinguished from other branched Horsetails with ease if the brown cone-bearing stem is present; distinguished with some difficulty in its absence. The sterile stems are highly variable and not particularly distinctive. Look for these characteristics to distinguish Field Horsetail:
    • from Marsh Horsetail (Equisetum palustre) the very small central hollow of that species
    • from Meadow Horsetail (Equisetum pratense) the spicules of silica found on that species
    • from Wood Horsetail (Equisetum sylvaticum) the reddish brown teeth of the leaf sheaths and the compound branching of that species
  • Field Marks
    • short, brownish yellow ephemeral fertile stem which never "greens up"
    • four angled, ascending branches which do not further sub-divide
    • ability to thrive in harsh, sterile habitats where other Horsetails could not, such as railway embankments


  • Cosmopolitan in distribution; in North America from Newfoundland to Alaska and south to Georgia, Texas, and California.


  • Woods, fields, meadows and swamps, and moist soils alongside streams, rivers, and lakes, and in disturbed areas; also on dry and barren sites such as roadsides, borrow pits, and railway embankments.
  • Thrives in any soil but prefers damp, sandy, partially shaded areas.


  • Usually occurs in moist habitats that do not undergo frequent fire but is well adapted when fire does occur. Though top-killed by most fires, the rhizomes are not killed by even very hot fires because they are buried deep in the mineral soil.
  • Colonizes disturbed areas or new sites by wind-disseminated propagules, although this is probably rare.
  • Regenerates rapidly after fire. Frequency of occurrence usually unchanged or increased after fire. Gameteophyte establishment requires the presence of moist, exposed mineral soils (as well as a source of spores).



  • Native Americans and early settlers used tea made from Field Horsetail as a diuretic.
  • Used as a cough medicine for horses.
  • Source of dyes for clothing, lodges, and porcupine quills.
  • It was used for scouring and polishing objects.
  • The young shoots were eaten either cooked or raw.


  • Extracted silica is used in manufacture of remineralizing and diuretic medicinal products. Other potential uses of biogenic silica include industrial applications (abrasives, toothpaste, protective cloth, optical fibers, thickeners for paint, etc.), detergents, and cleaners.
  • Leaf-odor constituents were used widely in the 1970's in perfumes but are little used now. These constituents can be used as food flavors and flavor enhancers, and as animal repellants.
  • Can accumulate gold in its tissues, up to 4.5 ounces of gold per ton of fresh plant material. Its value in this regard is primarily as an indicator plant rather than as a commercial source of gold
  • A noxious weed in Australia and many other locales.


  • Primary means of reproduction is asexual; conditions for the production of gametophytes from spores are limited and relatively rare.
  • Asexual reproduction: Spreads from extensive rhizomes. Even short segments of broken rhizomes will sprout. Overwintering buds develop at the nodes of the rhizomes.
  • Sexual reproduction:
    • Spores are equipped with elaters, long appendages that expand and contract with changes in humidity. Elaters function to dig the spore into the soil and to tangle spores together, thereby creating a larger propagule and increasing the probability that prothalli will be close enough to ensure fertilization.
    • Elaters may also aid in wind dissemination. Spores released by the cone bearing stems are dispersed by wind or water. The spores are thin-walled, short-lived, and quickly germinate under moist conditions.
    • Spores germinate to form prothalli: tiny plants only a few cell layers thick that are usually either male or female, producing only antheridia or archegonia, respectively. Swimming sperm are released by the antheridia and require water for transport to the egg-containing archegonia.
    • After fertilization takes place, the sporophytic generation (the identifiable large plant) develops in place, growing out of the prothallus.


  • Division most successful method.


  • Hardy to USDA Zone 3 (average minimum annual temperature -40ºF)
  • Not generally cultivated
  • Considered a weed in many of the world's crops but seldom the worst offender. Probably toxic to surrounding vegetation due to high levels of alkaloids.
  • Difficult to exterminate once established.
  • Sensitive to moisture stress; drought conditions result in a reduction in the production of new shoots.



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Last Updated on 26 February, 2004