Horsetail

Field 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. It is currently only found along the Waiau Toa/Clarence River in North Canterbury. 

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 can grow over 2m deep and are 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 vehicles (particularly 4WDs), gravel extraction, 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 and displaces pasture.

Management approach

Horsetail is declared an unwanted organism by the Ministry for Primary Industries (MPI) because it is capable of causing harm to the natural environment, physical resources or human health in Aotearoa/New Zealand.

These species pose a high risk to our environment, economy, recreation, and cultural values.

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.

Consider lower-risk alternatives for your garden, such as native plants.

Control

Do not attempt to undertake control of horsetail yourself. Report any sightings to us.