Equisetum arvense, common horsetail (native)
Fern

Equisetum arvense

common horsetail (native)

Equisetaceae

Circumboreal; North America, Europe, Asia

At a Glance

TypeFern
HabitUpright
FoliageDeciduous
Height6-24 inches (15-60 cm)
Width12-36 inches (30-90 cm)
Maturity3 years

Growing Zones

USDA Hardiness Zones

2 - 9
Zone 2
Zone 3
Zone 4
Zone 5
Zone 6
Zone 7
Zone 8
Zone 9
These zones indicate the coldest temperatures this plant can typically survive.
Frost Tolerancehardy

Key Features

Deer Resistant
Native to North America
Maintenancehigh

Overview

Equisetum arvense is a native, rhizomatous, spore-bearing perennial in the family Equisetaceae reaching 6–24 inches (15–60 cm) tall and spreading indefinitely via deep, branching rhizomes. This is a non-flowering vascular plant; it is classified with ferns and fern allies, not flowering plants. Two types of aerial stems are produced. Fertile stems emerge in early spring, pale tan to pinkish-brown, unbranched, jointed, 4–10 inches (10–25 cm) tall, topped by a cone-like strobilus that releases green spores. Fertile stems wither after spore release. Vegetative stems emerge shortly after, green, jointed, 6–24 inches (15–60 cm) tall, with whorls of slender green branches at each node, giving a bottle-brush or miniature-pine-tree appearance. Leaves are reduced to small, fused, toothed sheaths at each node. Stem surfaces contain silica, giving them a rough, gritty texture. The rhizome network extends 3–6 feet (0.9–1.8 m) deep and spreads laterally 10–15 feet (3–4.5 m) from the parent plant, with tuber-like nodules that store energy reserves. Rhizome fragments as small as 0.5 inch (1 cm) regenerate. The extremely deep rhizome system and silica-reinforced stems make this one of the most persistent native weeds in moist garden and agricultural soils. Toxic to horses when consumed in hay; the thiaminase enzyme in the foliage destroys vitamin B1.

Native Range

Circumboreal distribution: native across North America, Europe, and Asia, occurring from sea level to approximately 8,500 feet (2,600 m). Found in moist to wet soils along streambanks, ditches, roadsides, garden beds, poorly drained fields, and construction sites. Present in all 50 U.S. states and all Canadian provinces. One of the oldest living plant lineages, with fossil relatives dating to the Carboniferous period (over 300 million years ago).

Suggested Uses

Used in botany courses as a living example of a fern ally (sphenophyte), demonstrating jointed stems, reduced leaves, spore reproduction, and silica deposition. The Carboniferous-era fossil relatives of Equisetum reached tree size; the modern species is used to teach plant evolution and paleobotany. Studied in weed biology as a model for deep-rhizome persistence. Stems historically used as a natural abrasive for polishing metal and wood (scouring).

How to Identify

Identified by the jointed, ribbed, hollow stems with whorled branches at each node and the toothed sheaths replacing true leaves. Distinguished from Equisetum hyemale (scouring rush) by the branching vegetative stems (versus unbranched stems in E. hyemale). The early spring fertile stems topped by the strobilus (spore cone) are distinctive and precede the vegetative stems by 2–4 weeks. Stems have a gritty texture due to silica deposits; rubbing a stem between fingers produces a scratchy sensation.

Appearance

Size & Dimensions

Height6" - 2'
Width/Spread1' - 3'

Reaches mature size in approximately 3 years

Colors

Foliage Colors

green

Fall Foliage Colors

no change

Bloom Information

Does not flower. Strobili (spore cones) are produced at the tips of pale, unbranched fertile stems in March through April in the Pacific Northwest. Spores are green, ephemeral, and viable for only a few days after release. Strobili emerge before vegetative stems and wither within 2–3 weeks. Vegetative stems persist from April through the first hard frost.

Detailed Descriptions

Flower Description

None (spore-bearing, not flowering)

Foliage Description

Green, whorled scale-like leaves fused into toothed sheaths at stem nodes; vegetative stems with whorled green branches

Growing Conditions

Sun Requirements

Full Sun
Partial Shade
Full Shade
Requires 2-10 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range4.5 - 7.5(Neutral)
357912
Soil Types
loamclaysandsilt
Drainage
moist

Water & Climate

Water Needs

High

Frost Tolerance

hardy

Time to Maturity

2-3 years

Care & Maintenance

Care Guide

Native species managed as a weed in garden and agricultural settings due to the extremely deep, persistent rhizome network. Hand-pulling removes aerial stems but does not reach the deep rhizome system at 3–6 feet (0.9–1.8 m) depth. Repeated removal of aerial stems every 2–3 weeks throughout the growing season for 3–5 years gradually depletes rhizome energy reserves. Tilling fragments rhizomes and can spread infestations. Improving soil drainage reduces vigor, as the species is most competitive in persistently moist soils. Dense, opaque landscape fabric suppresses aerial growth but does not kill deep rhizomes; stems will re-emerge at fabric edges or through gaps. The silica content makes stems resistant to decomposition. Toxic to horses when consumed in hay; contaminated hay should not be fed to equines.

Pruning

No pruning applicable. Aerial stems are cut or pulled repeatedly to deplete rhizome reserves. Cutting at ground level every 2–3 weeks prevents spore production on fertile stems and photosynthate return to rhizomes from vegetative stems. Complete eradication from established sites is rarely achievable due to the depth and extent of the rhizome network.

Maintenance Level

high

⚠️ Toxicity Warning

Toxic to pets