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Equisetum arvense

Field Horsetail

At a Glance: Succulent, hollow, jointed stems with whorls of branches.

Height: 6-24 inches (15-60 cm).
Growth Form: Fern.
Stems: Stems have regularly spaced nodes or joints; two stem types - sterile stems, which are more common and last longer with 10-12 ridges, and fertile stems, which produce spores in early spring and soon whither.
Leaves: Reduced to tiny scales that are fused into 6-14 sheaths at stem nodes. Dense whorls of branches (often mistaken for leaves) form at stem nodes; branches are 1-1.5 mm thick, sometimes branch again.
Flowers: Horsetails reproduce by spores, and do not have flowers; green spores are produced in flesh-colored cone at tip of fertile stem.
Fruits: Fertile stems appear before sterile stems, unbranched; spore cone at tip. New shoots emerge mid-February to early May; shape: blunt-tipped cones; size: fertile stems 30 cm (12 in) tall, 8 mm thick; cones 2-3.5 cm long; color: whitish to flesh colored (become brownish just before withering).


Photo © 2003, Starflower Foundation

Sun/Shade Tolerance	Hydrology	Elevation Range
full sun > 80% mostly sunny 60%-80% partial sun and shade 40%- 60% mostly shady 60%-80% full shade > 80%	wet moist dry Wetland Indicator Status:	Below 3000 meters. low elevation mid elevation sub-alpine high elevation

Soil Preferences
sandy soils gravelly soils clay soils muddy soils peaty soils	well drained soils shallow soils deep soils acidic soils basic soils	humic soils nutrient rich soils nutrient poor soils mineral soils organic soils

Habitat Preferences
Aquatic and Wetland: Ponds or lakes Shallow pools Sloughs Swales or wet ditches Seasonally inundated areas Marshes or swamps Aquatic bed wetlands Emergent wetlands Scrub-shrub wetlands Forested wetlands Bogs, fens Seeps, springs Shorelines and Riparian: Lake shores Bog margins Streams or rivers Stream or river banks Riparian corridors River bars Floodplains Bottomlands Alluvial areas	Saltwater Areas: In or near saltwater Mud flats Tidal areas Estuaries Saltmarshes Brackish water Seashores Coastal dunes or beaches Rocky or Gravelly Areas: Coastal bluffs Cliffs Rocky slopes Outcrops Crevices Glacial outwash Gullies Slide areas Sub-alpine and Alpine: Heaths Snow beds Tundra Avalanche tracks	Forests and Thickets: Forests and woods Open forests Coniferous forests Old growth forests Deciduous forests Mixed forests Nurse logs Forest edges, openings, or clearings Thickets Meadows and Fields: Pastures or fields Meadows or grassy areas Mossy areas Disturbed Areas: Roadsides Trailsides Logged sites Burned areas Disturbed sites

Wildlife Value

(data not available)

Ethnobotanical Uses and Other Facts

Material Uses: The silicated stems were used by Native Americans (and still used by some people today) to start hand-drilled fires.
Food Uses: Some people cook and eat the young fertile shoots as a sort of asparagus substitute, its best to eat other early spring wild plants. Ancient Romans ate young, fertile shoots as if they were asparagus. They also used them to make tea and as a thickening powder.
Toxicity: Toxic to horses..

Ecological Importance: Often exists in thick stands of shoots that can choke other plants. Requires prolonged effort to remove from sites due to rhizomes. The fertile stems of common horsetail appear in early spring before the vegetative stems have grown tall enough to block spore dispersal by the wind. The spores have appendages on them that curl when wetted and uncurl when dried, which helps disperse the spores and move them deeper in the soil.

Name Info: arvense means of the fields. Horsetails are named for a fanciful resemblance between a horses tail and the plants sterile green stems with whorls of wire-like branches.
Interesting Facts: One of the most widespread plants in the world. Often considered a bad garden weed. Horsetails, also known as scouring rushes, have silica in their tissues, which makes them gritty. A ton of horsetails can accumulateas much as 4.5 ounces of gold in its cells, but profitable harvesting is impossible. Can be used as an emery board substitute or crumple in your hands to make a gentle scour, like fine-textured sandpaper, for dishes. Herbalists have used it, though not to a great extent, to heal broken bones. The first vascular plant to send green shoots up through the debris of the 1980 eruption of Mt. St. Helens.

Suggested References

Cooke, S.S. A Field Guide to the Common Wetland Plants of Western Washington and Northwetern Oregon. Seattle Audubon Society and Washington Native Plant Society. Page 380.
Guard, B.J. 1995. Wetland Plants of Oregon & Washington. Lone Pine Publishing. Page 195.
Hickman, J.C., ed. 1993. The Jepson Manual: Higher Plants of California. University of California Press. Page 95.
Hitchcock, C.L., A. Cronquist. 1973. Vascular Plants of the Pacific Northwest. University of Washington Press. Page 44.
Jacobson A.L. 2001. Wild Plants of Greater Seattle. Published by author. Page 372.
Lyons, C., W. Merilees. Trees and Shrubs to Know in Washington and British Columbia. Lone Pine Publishing. Page 344.
Pojar, J., A. Mackinnon. 1994. Plants of the Pacific Northwest Coast. Lone Pine Publishing. Page 430.
Taylor, R.J., G.W. Douglas. 1995. Mountain Plants of the Pacific Northwest. Mountain Press Publishing Company. Page 8.
Whitson, T.D., ed. 2001. Weeds of the West. University of Wyoming. Page 306.

The landscaping and restoration information provided on this page is taken from Starflower Foundation Image Herbarium. All photographs © Starflower Foundation unless otherwise noted.