Equisetum species are known horsetails or living fossils as they are the only living genus in Equisetaceae, a family of vascular plants which reproduce by spores rather than seeds. Horsetail species have a rush like appearance and are highly competitive near water and toxic to livestock.
Description - Field horsetail Equisetum arvense
- Also known as: common horsetail, scouring rush, horsetail
- Stems are slender, course, up to 80cm tall.
- Stems are ridged, jointed, and hollow with no leaves.
- Spores are produced in oval cones at the top of shorter brown and white stems in early spring.
- Extensive network of black underground rhizomes.
Close-up of field horsetail’s jointed stem, with fine green branches arranged in rings. Photo: Benjamin Schedl
Field horsetail’s upright green stems and spreading branches give it a feathery appearance. Photo: Trevor James
A dense patch of field horsetail, showing green branched stems alongside pale, cone-tipped shoots. Photo: Trevor James
Field horsetail’s pale, unbranched shoots carry spore-producing cones at their tips. Photo: Trevor James
Description - Rough horsetail Equisetum hyemale
- Also known as: Dutch rush, pewterwort, snake grass
- Stems are erect, evergreen and up to 180cm tall.
- Stems have distinctive black banded joints, resembling bamboo.
- Spores are produced in brown or cream oval cones. They don't produce flowers.
- Rhizomes can grow over 2m deep and are tuberous.
Rough horsetail’s green, ridged stems have distinctive pale bands edged in black. Photo: Trevor James
A cone at the tip of a rough horsetail stem produces spores. Photo: Trevor James
Rough horsetail growing in a dense stand of upright, segmented stems. Photo: Daniel Sullivan
Close-up of the banded joint and fine ridges on a rough horsetail stem. Photo: Carson B
A thick clump of rough horsetail growing in a garden bed. Photo: Zamaria Baugh
For both species
- Vegetative spread from rhizomes, dispersed by water and soil movement. Sporing cones are rarely produced in New Zealand.
- 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.
Management and control of horsetail
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