Horsetail

Horsetail is an erect perennial fern that may look like very green bamboo or large asparagus stems. It is highly competitive near water and toxic to livestock.

Description

• Stems are rush-like, erect and with distinct jointed bands.
• Leaves may be fern-like or feathery with some resemblance to dill or fennel.
• Spore cones grow on the ends of fertile stems in spring.
• Above-ground plant parts die back in winter.
• Rhizomes are less than 1m deep and tuberous.
• Spores are seldom produced in New Zealand.
• Vegetative spread from rhizomes, stem fragments, and tubers, dispersed by water and soil movement.
• Human-mediated dispersal through contamination of machinery and deliberate plantings.
• Habitats include near waterbodies, wetlands, drains, croplands, roadsides and wastelands.

What you need to know

Highly competitive in wetlands and near waterbodies, excludes other vegetation and alters nutrient cycles. Toxic to livestock.

Management approach

Horsetail is an unwanted organism regulated under the National Plant Pest Accord.

National Pest Plant Accord (NPPA)

The NPPA prevents the sale, distribution and propagation of specified pest plants within Aotearoa/New Zealand and is administered by the Ministry for Primary Industries (MPI).

Rules

Any species declared a pest, including unwanted organisms, cannot be sold or be in a place where plants are being sold. Pest plants cannot be propagated, bred, multiplied, communicated, released, caused to be released, or otherwise spread.

See the MPI website for more information on the NPPA.

Consider removing this invasive species from your property and consult your local council for appropriate disposal. Consider lower-risk alternatives for your garden, such as native plants.

Control

Site Management

Follow up treated areas three times per year. Encourage natural regeneration of native plants or replant treated areas where possible after two to three treatments to establish dense ground cover and minimise reinvasion.

Physical control

Dig out or pull out.

Plant parts requiring disposal: all plant parts.

Contact your local council for appropriate disposal locations.

Chemical control

No qualifications: Cut stump and paste freshly cut base of stems with metsulfuron gel.

Certified handler/experienced agrichemical user: Foliar spray with 5g metsulfuron-methyl per 10L of water and 20ml penetrant.

Caution: When using any herbicide or pesticide please read the label thoroughly to ensure that all instructions and safety requirements are followed.

Biological control

Keep an eye out for field horsetail weevil (Grypus equiseti).