Weeds: Horsetails (Scouringrush) – Equisetum spp.

categories: F-H Weeds

revision date: 2024-06-22 08:11

  • Family: Equisetaceae
  • Cycle: Perennial
  • Plant type: Other
Horsetail.
Horsetail
Photo by: R. Parker

Biology

Field horsetail (Equisetum arvense) grows from a perennial, creeping root system. The rhizomes are brown, somewhat woolly, and bear small tubers. Two types of stems emerge in the spring. Tiny modified leaves form black “teeth” at the nodes of the stems. Fertile stems (6-12 inches tall) are tan, jointed, and unbranched, with an inch-long, spore-bearing “cone” at the tip. Sterile stems (12-18 inches tall) are green and slender, with green whorls of leafless, four-angled, fine branches at each joint. Both types of stems are rough to the touch, because the plants accumulate silica in the stems. Sterile stems die back in the fall. The root system extends deep into the soil and spreads extensively, making this species very difficult to control. Giant horsetail (E. telmateia) closely resembles field horsetail, but is taller, with more and larger (18 inches or more) fertile stems in the spring. Giant horsetail “cones” reach up to four inches long. Scouringrush (E. hyemale) has only fertile stems. All stems are green, unbranched, and produce small “cones” at the tips. The stems can reach four feet in height and frequently remain green through the winter. All types of horsetail are characterized by hollow, segmented stems that are rough to the touch. SPECIAL INFORMATION: All species of horsetails are considered toxic to livestock. In OREGON, giant horsetail (E. telmateia) is on the noxious weed quarantine list, which prohibits sale, purchase, and transport of plants, seeds, and plant parts.

Habitat

Horsetails are found primarily in moist to wet areas. Scouringrush is common along roadsides and ditch banks. Field horsetail is found primarily in moist to wet areas, but can survive in drier areas once established. Field horsetail is a common weed of gardens, pastures, and home landscapes.

Management Options

Use Integrated Pest Management (IPM) for successful plant problem management.

Non-chemical Management

Select non-chemical management options as your first choice!

  • Maintaining a healthy planting or turf area to provide competition will prevent weed establishment.
  • Reduce weed infestation by handpulling weeds.
  • Inorganic mulches, such as plastic, commercial “weed barrier” fabrics and other materials such as roofing paper, is an effective weed management option. Cover inorganic mulches with a thin layer of soil or organic mulch.

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

  • Apply in winter or early spring when soil is cool and moisture is available.
  • Bark mulch may be spread over treated area to reduce volatilization.
  • There is a product available to professional applicators which can be applied to turfgrass in severe cases.
  • NOTE: Some ingredients listed here are only available in combination.
  • Read the label carefully on combination products to make sure the product is suitable for your specific situation.

Landscape areas

  • dichlobenil

Turf areas

  • No products approved for use in turf.

Bare ground areas

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Additional Images